RESUMO
As massive amounts of carbon dioxide (CO2) have been emitted into the atmosphere causing severe global warming problems, developing carbon-negative techniques to control atmospheric CO2 concentrations is enormously urgent. Herein, by coupling the direct atmosphere CO2 capture adsorbent ZSM-5 with the CO2 reduction photocatalyst NiV2Se4, we present the first synergistic approach for concentrating and converting atmospheric CO2 into C2 solar fuels. A C2H6 yield of 1.85 µmol g-1 h-1 has been achieved in the air, outperforming state-of-the-art direct atmospheric CO2 conversion photocatalysts. Comprehensive characterizations show that ZSM-5 enhances CO2 capture from the atmosphere, improving the interfacial interaction of CO2 on the NiV2Se4 surface for C-C coupling of CH3* to form C2H6. This work demonstrates the first example of integrating direct CO2 capture material with a CO2 reduction photocatalyst for atmospheric CO2 capture and utilization, which paves the way for the negative-carbon technology development under worldwide carbon-neutral pressure.
RESUMO
Highly selective photoreduction of CO2 to valuable hydrocarbons is of great importance to achieving a carbon-neutral society. Precisely manipulating the formation of the Metal1 â â â C=Oâ â â Metal2 (M1 â â â C=Oâ â â M2 ) intermediate on the photocatalyst interface is the most critical step for regulating selectivity, while still a significant challenge. Herein, inspired by the polar electronic structure feature of CO2 molecule, we propose a strategy whereby the Lewis acid-base dual sites confined in a bimetallic catalyst surface are conducive to forming a M1 â â â C=Oâ â â M2 intermediate precisely, which can promote selectivity to hydrocarbon formation. Employing the Ag2 Cu2 O3 nanowires with abundant Cuâ â â Ag Lewis acid-base dual sites on the preferred exposed {110} surface as a model catalyst, 100 % selectivity toward photoreduction of CO2 into CH4 has been achieved. Subsequent surface-quenching experiments and density functional theory (DFT) calculations verify that the Cuâ â â Ag Lewis acid-base dual sites do play a vital role in regulating the M1 â â â C=Oâ â â M2 intermediate formation that is considered to be prone to convert CO2 into hydrocarbons. This study reports a highly selective CO2 photocatalyst, which was designed on the basis of a newly proposed theory for precise regulation of reaction intermediates. Our findings will stimulate further research on dual-site catalyst design for CO2 reduction to hydrocarbons.
RESUMO
Persulfate (PS, S2O82-) activation through transition metal sulfides (TMS) has gained increasing attention since it can decompose a wide variety of refractory halogenated organic compounds in groundwater and wastewater. However, the processes of PS activation by TMS and particularly the formation of â¢OH radical under anoxic and acidic conditions (pH â¼2.8) remain elusive. Herein, by employing mixed redox-couple-involved chalcopyrite (CuFeS2) (150 mg/L) nanoparticles for PS (3.0 mM) activation, 96% of trichloroethylene was degraded within 120 min at pH 6.8 under visible light irradiation. The combination of experimental studies and theoretical calculations suggested that the Cu(I)/Fe(III) mixed redox-couple in CuFeS2 plays a crucial role to activate PS. Cu(I) acted as an electron donor to transfer electron to Fe(III), then Fe(III) served as an electron transfer bridge as well as a catalytic center to further donate this received electron to the O-O bond of PS, thus yielding SO4â¢- for trichloroethylene oxidation. Moreover, for the first time, â¢OH radicals were found to form from the catalytic hydrolysis of PS onto CuFeS2 surface, where S2O82- anion was hydrolyzed to yield H2O2 and these ensuing H2O2 were further transformed into â¢OH radicals via photoelectron-assisted O-O bond cleavage step. Our findings offer valuable insights for understanding the mechanisms of PS activation by redox-couple- involved TMS, which could promote the design of effective activators toward PS decomposition for environmental remediation.