CO_(2) is the most cost-eff ective and abundant carbon resource,while the reverse water-gas reaction(rWGS)is one of the most eff ective methods of CO_(2) utilization.This work presents a comparative study of rWGS acti...CO_(2) is the most cost-eff ective and abundant carbon resource,while the reverse water-gas reaction(rWGS)is one of the most eff ective methods of CO_(2) utilization.This work presents a comparative study of rWGS activity for perovskite systems based on AFeO_(3)(where A=Ce,La,Y).These systems were synthesized by solution combustion synthesis(SCS)with diff erent ratios of fuel(glycine)and oxidizer(φ),diff erent amounts of NH 4 NO_(3),and the addition of alumina or silica as supports.Various techniques,including X-ray diff raction analysis,thermogravimetric analysis,Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy,energy-dispersive X-ray spectroscopy,N 2-physisorption,H_(2) temper-ature-programmed reduction,temperature-programmed desorption of H_(2) and CO_(2),Raman spectroscopy,and in situ FTIR,were used to relate the physicochemical properties with the catalytic performance of the obtained composites.Each specifi c perovskite-containing system(either bulk or supported)has its own optimalφand NH_(4) NO_(3) amount to achieve the highest yield and dispersion of the perovskite phase.Among all synthesized systems,bulk SCS-derived La-Fe-O systems showed the highest resistance to reducing environments and the easiest hydrogen desorption,outperforming La-Fe-O produced by solgel combustion(SGC).CO_(2) conversion into CO at 600°C for bulk ferrite systems,depending on the A-cation type and preparation method,follows the order La(SGC)<Y<Ce<La(SCS).The diff erences in properties between La-Fe-O obtained by the SCS and SGC methods can be attributed to diff erent ratios of oxygen and lanthanum vacancy contributions,hydroxyl coverage,morphology,and free iron oxide presence.In situ FTIR data revealed that CO_(2) hydrogenation occurs through formates generated under reaction conditions on the bulk system based on La-Fe-O,obtained by the SCS method.γ-Al_(2)O_(3) improves the dispersion of CeFeO_(3) and LaFeO_(3) phases,the specifi c surface area,and the quantity of adsorbed H_(2) and CO_(2).This led to a signifi cant increase in CO_(2) conversion for supported CeFeO_(3) but not for the La-based system compared to bulk and SiO_(2)-supported perovskite catalysts.However,adding alumina increased the activity per mass for both Ce-and La-based perovskite systems,reducing the amount of rare-earth components in the catalyst and thereby lowering the cost without substantially compromising stability.展开更多
Porous metal–organic frameworks(MOFs) have been recently discovered to be efficient catalysts for energy applications and green technologies. Here, we report on a scalable catalytic platform using Cu–based MOFs for ...Porous metal–organic frameworks(MOFs) have been recently discovered to be efficient catalysts for energy applications and green technologies. Here, we report on a scalable catalytic platform using Cu–based MOFs for electrocatalytic alkaline hydrogen evolution reaction. First, the solvothermal synthesis of Cu–BTC MOFs(BTC = 1,3,5–benzenetricarboxylate) at 85 ℃ and a 1:60 ligand–to–solvent ratio allowed for minimizing the chemical consumption. Second, the obtained platform demonstrated enhanced electrochemical performance compared with commercially available Cu–based MOFs, with a potential of –230 versus –232 eV, logarithm of the current density of –3.6 versus –4.2 cm2, and electrochemical surface area of 75 versus 25 cm2per cm2of geometric area, respectively. Morphological and Raman analyses also revealed that the high concentration of defects in the obtained submicron Cu–BTC MOFs can contribute to their improved catalytic performance. Thus, our findings pave the way to the low–cost synthesis of energy–efficient MOF–based catalysts for hydrogen production.展开更多
基金The research was carried out within the State Assignment of the Ministry of Science and Higher Education of the Russian Federation(project No.FFUG-2024-0036)。
文摘CO_(2) is the most cost-eff ective and abundant carbon resource,while the reverse water-gas reaction(rWGS)is one of the most eff ective methods of CO_(2) utilization.This work presents a comparative study of rWGS activity for perovskite systems based on AFeO_(3)(where A=Ce,La,Y).These systems were synthesized by solution combustion synthesis(SCS)with diff erent ratios of fuel(glycine)and oxidizer(φ),diff erent amounts of NH 4 NO_(3),and the addition of alumina or silica as supports.Various techniques,including X-ray diff raction analysis,thermogravimetric analysis,Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy,energy-dispersive X-ray spectroscopy,N 2-physisorption,H_(2) temper-ature-programmed reduction,temperature-programmed desorption of H_(2) and CO_(2),Raman spectroscopy,and in situ FTIR,were used to relate the physicochemical properties with the catalytic performance of the obtained composites.Each specifi c perovskite-containing system(either bulk or supported)has its own optimalφand NH_(4) NO_(3) amount to achieve the highest yield and dispersion of the perovskite phase.Among all synthesized systems,bulk SCS-derived La-Fe-O systems showed the highest resistance to reducing environments and the easiest hydrogen desorption,outperforming La-Fe-O produced by solgel combustion(SGC).CO_(2) conversion into CO at 600°C for bulk ferrite systems,depending on the A-cation type and preparation method,follows the order La(SGC)<Y<Ce<La(SCS).The diff erences in properties between La-Fe-O obtained by the SCS and SGC methods can be attributed to diff erent ratios of oxygen and lanthanum vacancy contributions,hydroxyl coverage,morphology,and free iron oxide presence.In situ FTIR data revealed that CO_(2) hydrogenation occurs through formates generated under reaction conditions on the bulk system based on La-Fe-O,obtained by the SCS method.γ-Al_(2)O_(3) improves the dispersion of CeFeO_(3) and LaFeO_(3) phases,the specifi c surface area,and the quantity of adsorbed H_(2) and CO_(2).This led to a signifi cant increase in CO_(2) conversion for supported CeFeO_(3) but not for the La-based system compared to bulk and SiO_(2)-supported perovskite catalysts.However,adding alumina increased the activity per mass for both Ce-and La-based perovskite systems,reducing the amount of rare-earth components in the catalyst and thereby lowering the cost without substantially compromising stability.
基金This work was supported by Russian Science Foundation(22-73-10069“Design and application of fl exible Metal organic frameworks for photonics devices,”the chemical part and structural analysis of developed MOFs)The of stability MOFs was conducted under the fi nancial support of the Ministry of Science and Higher Education of the Russian Federation as part of the World-Class Research Center program:Advanced Digital Technologies(contract No.075-15-2022-311 dated 20.04.2022)The authors thank the Engineering Centre of Saint Petersburg State Institute of Technology for PXRD analysis.
文摘Porous metal–organic frameworks(MOFs) have been recently discovered to be efficient catalysts for energy applications and green technologies. Here, we report on a scalable catalytic platform using Cu–based MOFs for electrocatalytic alkaline hydrogen evolution reaction. First, the solvothermal synthesis of Cu–BTC MOFs(BTC = 1,3,5–benzenetricarboxylate) at 85 ℃ and a 1:60 ligand–to–solvent ratio allowed for minimizing the chemical consumption. Second, the obtained platform demonstrated enhanced electrochemical performance compared with commercially available Cu–based MOFs, with a potential of –230 versus –232 eV, logarithm of the current density of –3.6 versus –4.2 cm2, and electrochemical surface area of 75 versus 25 cm2per cm2of geometric area, respectively. Morphological and Raman analyses also revealed that the high concentration of defects in the obtained submicron Cu–BTC MOFs can contribute to their improved catalytic performance. Thus, our findings pave the way to the low–cost synthesis of energy–efficient MOF–based catalysts for hydrogen production.
