Journal of materials chemistry. A, Materials for energy and sustainability, 2023
A rational approach for construction of superior model electrocatalysts for nitrogen oxidation to... more A rational approach for construction of superior model electrocatalysts for nitrogen oxidation to nitric acid and their mechanistic insights, protocols, and various challenges that would be a viable alternative to the century-old Ostwald process.
Quantum dots are novel nanomaterials due to their nanoscale size and diverse characteristics. The... more Quantum dots are novel nanomaterials due to their nanoscale size and diverse characteristics. They serve as low-cost visual sensors, widely studied for sensing applications, including ratiometric combinations, to enhance the limit of detection.
Ammonia (NH3) is regarded as a renewable energy source as well as an important molecule for agric... more Ammonia (NH3) is regarded as a renewable energy source as well as an important molecule for agricultural applications. The energy‐intensive Haber‐Bosch method produces large amounts of CO2 gas during ammonia production. As an alternative, there has recently been much interest in the electrocatalytic production of NH3 via the electrochemical nitrogen reduction reaction (ENRR) process utilizing renewable energy under ambient condition. Herein, we report a conducting carbon–supported manganese phthalocyanine electrocatalyst as an efficient electrocatalyst for ENRR applications. The MnPc electrocatalyst exhibited the activity with an ammonia production rate of 61.8 μg h−1mg−1cat with Faradaic efficiency (FE) of 31.3% @–0.4 V vs. RHE, respectively, under ambient condition in 0.1 M HCl solution whereas MnPc/C electrocatalyst exhibited an enhanced the productivity with an ammonia yield rate of 127.7 μg h−1mg−1cat with FE of 35.3% @–0.4 V vs. RHE, respectively. The reliability of N origin i...
Green urea synthesis is a novel way to convert N2/NOx and CO2 as compared to the industrial metho... more Green urea synthesis is a novel way to convert N2/NOx and CO2 as compared to the industrial method, which is an expensive and high energy demanding process. Mechanistic insights of urea synthesis are important to increase efficiency of the process.
Electrochemical urea synthesis is a promising technology for carbon utilization. It is challengin... more Electrochemical urea synthesis is a promising technology for carbon utilization. It is challenging to widen CO2RR application. Herein, we report a CoPc–MoS2 system for promoting urea synthesis by C–N coupling...
Ammonia produced through the energy intensive Haber–Bosch process, undergoes catalytic oxidation ... more Ammonia produced through the energy intensive Haber–Bosch process, undergoes catalytic oxidation for the manufacture of commercial nitric acid in the age–old Ostwald process. This two–step energetically non–viable industrial process demands the quest of an alternative single step electrocatalysis from the last century. The quest ends up in optimism when we unravel a ten–electron pathway associated with electrochemical dinitrogen oxidation reaction (N2OR) to nitric acid by manganese phthalocyanine (MnPc) hierarchical nano–structures (HNs) at STP. The catalyst delivers nitric acid yield of 720 µmol h–1 g–1cat @ 1.9 V vs. RHE and F.E. of 17.32 % @ 1.7 V vs. RHE in 0.05 M HCl. The local co–ordination environment (Mn–N4) during electrocatalysis process is ensured by the XAFS study. DFT based calculations express that the Mn site of MnPc is the main active center for nitrogen adsorption for N2OR, suppressing the OER.
Ammonia (NH3) is a key agricultural component and a source of clean energy as a hydrogen mediator... more Ammonia (NH3) is a key agricultural component and a source of clean energy as a hydrogen mediator. Ammonia is produced by Haber Bosch process, resulting in massive energy consumption and severe environmental impact. It is a thriving challenge to design and develop efficient nitrogen reduction reaction (NRR) and nitrate reduction reaction (NO3RR) electrocatalysts using variable reactants sources for ammonia synthesis at STP. 2D graphene sheets wrapped cobalt phthalocyanine nanotube to obtain (1D-2D) heterostructure, which serve as an active bifunctional electrocatalyst for NRR and NO3RR. At –0.2 V vs RHE, the electrocatalyst displayed NH3 yield rate of 58.82 μg h−1 mg−1 cat and a Faradaic efficiency (FE) of 95.12 % for NO3RR and 143.38 μg h−1 mg−1 cat and 43.69 % for NRR. Isotope tracing experiment confirmed the origin of ammonia synthesis. DFT calculations through Bader charge analysis revealed that charge transfer from the RGO to the Co-N4 sites in CoPc aided in the formation of NN...
The industrial production of urea involves two sequential steps, reaction of nitrogen and hydroge... more The industrial production of urea involves two sequential steps, reaction of nitrogen and hydrogen to form ammonia followed by the reaction of the ammonia with carbon dioxide, so the process is capital expensive, massive energy consuming and complex synthesis process with multiple cycles to increase the production efficiency. The electrocatalytic C–N coupling reaction to specifically produce urea by simultaneous activation followed by co-reduction of carbon dioxide (CO2) and nitrogen sources (N2, NO2– or NO3–) at ambient condition presents a sustainable and eco-friendlier alternate route for urea production by a single step process. However, there are several challenges like adsorption capabilities of the reactants on the substrates followed by activation, suppression of hydrogen evolution reaction and finally effective C–N bond formation to specifically produce urea. In this work we showcase the road map of the electrocatalytic green urea production, with concise yet precise discus...
Journal of Materials Science: Materials in Electronics, 2022
Rare earth-doped phosphor materials have always remained in focus for excellent luminescence prop... more Rare earth-doped phosphor materials have always remained in focus for excellent luminescence properties. Herein we have synthesized Yb3+ and Er3+-doped BaWO4 nanophosphor via facile hydrothermal method with red and green region emissions by 980 nm excitation. Red and green region emissions were observed due to 4F9/2 → 4I15/2 and 2H11/2/4S3/2 → 4I15/2 transitions, respectively, of Er3+, where Yb3+ acts as a sensitizer. The sample characterization was done using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS) techniques. The consequences of different concentrations of activator ion (Er3+) in BaWO4: Yb3+, Er3+ were studied from luminescence perspective in detail. The intensity of overall emission varied with altering the power of excitation that influences the photon transfer pathways. It was found that two-photon processes control both red and green emissions in the upconversion process. Decay behavior for both the emission was investigated. Thus, the tunable photoluminescence property suggests its potential in optoelectronic applications.
Electrocatalytic ammonia (NH3) synthesis through the nitrogen reduction reaction (NRR) under ambi... more Electrocatalytic ammonia (NH3) synthesis through the nitrogen reduction reaction (NRR) under ambient conditions presents a promising alternative to the famous century-old Haber-Bosch process. Designing and developing a high-performance electrocatalyst is a compelling necessity for electrochemical NRR. Specific transition metal based nanostructured catalysts are potential candidates for this purpose owing to their attributes such as higher actives sites, specificity as well as selectivity and electron transfer, etc. However, due to the lack of a well-organized morphology, lower activity, selectivity, and stability of the electrocatalysts make them ineffective at producing a high NH3 yield rate and Faradaic efficiency (FE) for further development. In this work, stable β-cobalt phthalocyanine (CoPc) nanotubes (NTs) have been synthesized by a scalable solvothermal method for electrochemical NRR. The chemically synthesized CoPc NTs show excellent electrochemical NRR due to high specific area, greater number of exposed active sites, and specific selectivity of the catalyst. As a result, CoPc NTs produced a higher NH3 yield of 107.9 μg h-1 mg-1cat and FE of 27.7% in 0.1 M HCl at -0.3 V vs RHE. The density functional theory calculations confirm that the Co center in CoPc is the main active site responsible for electrochemical NRR. This work demonstrates the development of hollow nanostructured electrocatalysts in large scale for N2 fixation to NH3.
Nitrogen-based fertilizers are necessary to increase the agricultural output since nitrogen is th... more Nitrogen-based fertilizers are necessary to increase the agricultural output since nitrogen is the most frequent rate-limiting product. The main ingredients in almost all nitrogen-based fertilizers are ammonia and nitric acid; demand for these substances is significantly driven by global population and food production. Over the next few decades, the size and value of the ammonia and nitric acid markets will continue to be largely influenced by global population, which will have a significant impact on energy utility. Ammonia is synthesized via the high energy demanding Haber-Bosch process, and in the Ostwald process, ammonia is catalytically oxidized to prepare industrial grade nitric acid. As industrial synthesis of nitric acid requires astronomical units of energy and emits greenhouse gases into the atmosphere at an alarming rate. Hence, there is an immediate need to find an eco–friendlier alternative route to produce nitric acid. In the approaching century, the most advantageous ...
Journal of materials chemistry. A, Materials for energy and sustainability, 2023
A rational approach for construction of superior model electrocatalysts for nitrogen oxidation to... more A rational approach for construction of superior model electrocatalysts for nitrogen oxidation to nitric acid and their mechanistic insights, protocols, and various challenges that would be a viable alternative to the century-old Ostwald process.
Quantum dots are novel nanomaterials due to their nanoscale size and diverse characteristics. The... more Quantum dots are novel nanomaterials due to their nanoscale size and diverse characteristics. They serve as low-cost visual sensors, widely studied for sensing applications, including ratiometric combinations, to enhance the limit of detection.
Ammonia (NH3) is regarded as a renewable energy source as well as an important molecule for agric... more Ammonia (NH3) is regarded as a renewable energy source as well as an important molecule for agricultural applications. The energy‐intensive Haber‐Bosch method produces large amounts of CO2 gas during ammonia production. As an alternative, there has recently been much interest in the electrocatalytic production of NH3 via the electrochemical nitrogen reduction reaction (ENRR) process utilizing renewable energy under ambient condition. Herein, we report a conducting carbon–supported manganese phthalocyanine electrocatalyst as an efficient electrocatalyst for ENRR applications. The MnPc electrocatalyst exhibited the activity with an ammonia production rate of 61.8 μg h−1mg−1cat with Faradaic efficiency (FE) of 31.3% @–0.4 V vs. RHE, respectively, under ambient condition in 0.1 M HCl solution whereas MnPc/C electrocatalyst exhibited an enhanced the productivity with an ammonia yield rate of 127.7 μg h−1mg−1cat with FE of 35.3% @–0.4 V vs. RHE, respectively. The reliability of N origin i...
Green urea synthesis is a novel way to convert N2/NOx and CO2 as compared to the industrial metho... more Green urea synthesis is a novel way to convert N2/NOx and CO2 as compared to the industrial method, which is an expensive and high energy demanding process. Mechanistic insights of urea synthesis are important to increase efficiency of the process.
Electrochemical urea synthesis is a promising technology for carbon utilization. It is challengin... more Electrochemical urea synthesis is a promising technology for carbon utilization. It is challenging to widen CO2RR application. Herein, we report a CoPc–MoS2 system for promoting urea synthesis by C–N coupling...
Ammonia produced through the energy intensive Haber–Bosch process, undergoes catalytic oxidation ... more Ammonia produced through the energy intensive Haber–Bosch process, undergoes catalytic oxidation for the manufacture of commercial nitric acid in the age–old Ostwald process. This two–step energetically non–viable industrial process demands the quest of an alternative single step electrocatalysis from the last century. The quest ends up in optimism when we unravel a ten–electron pathway associated with electrochemical dinitrogen oxidation reaction (N2OR) to nitric acid by manganese phthalocyanine (MnPc) hierarchical nano–structures (HNs) at STP. The catalyst delivers nitric acid yield of 720 µmol h–1 g–1cat @ 1.9 V vs. RHE and F.E. of 17.32 % @ 1.7 V vs. RHE in 0.05 M HCl. The local co–ordination environment (Mn–N4) during electrocatalysis process is ensured by the XAFS study. DFT based calculations express that the Mn site of MnPc is the main active center for nitrogen adsorption for N2OR, suppressing the OER.
Ammonia (NH3) is a key agricultural component and a source of clean energy as a hydrogen mediator... more Ammonia (NH3) is a key agricultural component and a source of clean energy as a hydrogen mediator. Ammonia is produced by Haber Bosch process, resulting in massive energy consumption and severe environmental impact. It is a thriving challenge to design and develop efficient nitrogen reduction reaction (NRR) and nitrate reduction reaction (NO3RR) electrocatalysts using variable reactants sources for ammonia synthesis at STP. 2D graphene sheets wrapped cobalt phthalocyanine nanotube to obtain (1D-2D) heterostructure, which serve as an active bifunctional electrocatalyst for NRR and NO3RR. At –0.2 V vs RHE, the electrocatalyst displayed NH3 yield rate of 58.82 μg h−1 mg−1 cat and a Faradaic efficiency (FE) of 95.12 % for NO3RR and 143.38 μg h−1 mg−1 cat and 43.69 % for NRR. Isotope tracing experiment confirmed the origin of ammonia synthesis. DFT calculations through Bader charge analysis revealed that charge transfer from the RGO to the Co-N4 sites in CoPc aided in the formation of NN...
The industrial production of urea involves two sequential steps, reaction of nitrogen and hydroge... more The industrial production of urea involves two sequential steps, reaction of nitrogen and hydrogen to form ammonia followed by the reaction of the ammonia with carbon dioxide, so the process is capital expensive, massive energy consuming and complex synthesis process with multiple cycles to increase the production efficiency. The electrocatalytic C–N coupling reaction to specifically produce urea by simultaneous activation followed by co-reduction of carbon dioxide (CO2) and nitrogen sources (N2, NO2– or NO3–) at ambient condition presents a sustainable and eco-friendlier alternate route for urea production by a single step process. However, there are several challenges like adsorption capabilities of the reactants on the substrates followed by activation, suppression of hydrogen evolution reaction and finally effective C–N bond formation to specifically produce urea. In this work we showcase the road map of the electrocatalytic green urea production, with concise yet precise discus...
Journal of Materials Science: Materials in Electronics, 2022
Rare earth-doped phosphor materials have always remained in focus for excellent luminescence prop... more Rare earth-doped phosphor materials have always remained in focus for excellent luminescence properties. Herein we have synthesized Yb3+ and Er3+-doped BaWO4 nanophosphor via facile hydrothermal method with red and green region emissions by 980 nm excitation. Red and green region emissions were observed due to 4F9/2 → 4I15/2 and 2H11/2/4S3/2 → 4I15/2 transitions, respectively, of Er3+, where Yb3+ acts as a sensitizer. The sample characterization was done using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS) techniques. The consequences of different concentrations of activator ion (Er3+) in BaWO4: Yb3+, Er3+ were studied from luminescence perspective in detail. The intensity of overall emission varied with altering the power of excitation that influences the photon transfer pathways. It was found that two-photon processes control both red and green emissions in the upconversion process. Decay behavior for both the emission was investigated. Thus, the tunable photoluminescence property suggests its potential in optoelectronic applications.
Electrocatalytic ammonia (NH3) synthesis through the nitrogen reduction reaction (NRR) under ambi... more Electrocatalytic ammonia (NH3) synthesis through the nitrogen reduction reaction (NRR) under ambient conditions presents a promising alternative to the famous century-old Haber-Bosch process. Designing and developing a high-performance electrocatalyst is a compelling necessity for electrochemical NRR. Specific transition metal based nanostructured catalysts are potential candidates for this purpose owing to their attributes such as higher actives sites, specificity as well as selectivity and electron transfer, etc. However, due to the lack of a well-organized morphology, lower activity, selectivity, and stability of the electrocatalysts make them ineffective at producing a high NH3 yield rate and Faradaic efficiency (FE) for further development. In this work, stable β-cobalt phthalocyanine (CoPc) nanotubes (NTs) have been synthesized by a scalable solvothermal method for electrochemical NRR. The chemically synthesized CoPc NTs show excellent electrochemical NRR due to high specific area, greater number of exposed active sites, and specific selectivity of the catalyst. As a result, CoPc NTs produced a higher NH3 yield of 107.9 μg h-1 mg-1cat and FE of 27.7% in 0.1 M HCl at -0.3 V vs RHE. The density functional theory calculations confirm that the Co center in CoPc is the main active site responsible for electrochemical NRR. This work demonstrates the development of hollow nanostructured electrocatalysts in large scale for N2 fixation to NH3.
Nitrogen-based fertilizers are necessary to increase the agricultural output since nitrogen is th... more Nitrogen-based fertilizers are necessary to increase the agricultural output since nitrogen is the most frequent rate-limiting product. The main ingredients in almost all nitrogen-based fertilizers are ammonia and nitric acid; demand for these substances is significantly driven by global population and food production. Over the next few decades, the size and value of the ammonia and nitric acid markets will continue to be largely influenced by global population, which will have a significant impact on energy utility. Ammonia is synthesized via the high energy demanding Haber-Bosch process, and in the Ostwald process, ammonia is catalytically oxidized to prepare industrial grade nitric acid. As industrial synthesis of nitric acid requires astronomical units of energy and emits greenhouse gases into the atmosphere at an alarming rate. Hence, there is an immediate need to find an eco–friendlier alternative route to produce nitric acid. In the approaching century, the most advantageous ...
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Papers by ASHADUL ADALDER