Abstract
Exfoliated 2D MAX Ti3AlC2 conductive cocatalyst anchored with g-C3N4/TiO2 to construct 2D/0D/2D het-erojunction has been explored for enhanced CO2 photoreduction in a fixed-bed and monolith photoreac-tor.The TiO2 particle sizes(NPs and MPs)were systematically investigated to determine effective metal-support interaction with faster charge carrier separation among the composite materials.When TiO2 NPs were anchored with 2D Ti3AlC2 MAX structure,10.44 folds higher CH4 production was observed com-pared to anchoring TiO2 MPs.Maximum CH4 yield rate of 2103.5 μmol g-1 h-1 achieved at selectivity 96.59％using ternary g-C3N4/TiO2/Ti3AlC2 2D/OD/2D composite which is 2.73 and 7.45 folds higher than using binary g-C3N4/Ti3AlC2 MAX and TiO2 NPs/Ti3AlC2 samples,respectively.A step-scheme(S-scheme)photocatalytic mechanism operates in this composite,suppressed the recombination of useful electron and holes and provides higher reduction potential for efficient CO2 conversion to CO and CH4.More im-portantly,when light intensity was increased by 5 folds,CH4 production rate was increased by 3.59 folds under visible light.The performance of composite catalyst was further investigated in a fixed-bed and monolith photoreactor and found monolithic support increased CO production by 2.64 folds,whereas,53.99 times lower CH4 production was noticed.The lower photocatalytic activity in a monolith photore-actor was due to lower visible light penetration into the microchannels.Thus,2D MAX Ti3AlC2 composite catalyst can be constructed for selective photocatalytic CO2 methanation under visible light in a fixed-bed photoreactor.
基金项目
Ministry of Higher Education()
Malaysia,for financial sup-port of this work under Fundamental Research Grant Scheme(RJ13000078515F384)
NETL
NSTL
万方数据