Rapid and highly selective conversion of CO2 to methanol by heterometallic porous ZIF-8

Commercial application of CO 2 -to-fuel technology has been mainly restricted due to low-cut CO 2 adsorption and activation by photocatalyst, thus contributing to low/impure fuel yield. Defect engineering of key CO 2 activators onto excellent CO 2 adsorbent along with in-situ & co-production of H adatoms could address these issues. Herein, we report rapid conversion of CO 2 to CH 3 OH in a photocatalytic system composed of Co x Mo y Zn 1−x−y ZIF-8 photocatalyst and NaBH 4 -assisted H adatoms production. Doping of Co & Mo into ZIF-8 provided active centers for CO 2 activation and structured highly efficient electron transport chains (ETCs) for selective conversion of continuous supply of CO 2 into CH 3 OH (99%). Conversion of CO 2 by Co x Mo y Zn 1−x−y ZIF-8 yields 9.96 mmole g cat -1 h -1 of CH 3 OH higher than reported ZIF-8 based photocatalyst in literature, and pristine ZIF-8, which only produced 94.2 µmole g -1 of carbon monoxide. Mechanistically, engineered doping of Co 0.25 /Mo 0.25 in Zn-ZIF-8 enhanced visible light absorption and mechanized ETCs due to d-orbitals and multiple redox states, which largely expediated CO 2 adsorption-activation. While in-situ & co-production of H adatoms from NaBH 4 and water spitting boost conversion of activated CO 2 to CH 3 OH. Interestingly, the controlled release of H adatoms from NaBH 4 maintained a requisite charge gradient across ETCs, which was proven to be another reason for the high yield and selectivity of CH 3 OH. 13 CO 2 analysis confirmed the source of C in CH 3 OH was supplied CO 2 , not by photocatalyst carbon that proved the stability of Co x Mo y Zn 1−x−y ZIF-8. We believe this work will be a step forward for commercializing revolutionary CO 2 -to-fuel technology, while results and novel interpretation will be key for multidisciplinary research. • Photocatalytic conversion of 10 mmole of CO 2 produced 9.96 mmole g cat -1 h -1 CH 3 OH. • Co/Mo doping into ZIF-8 facilitated direct conversion of CO 2 with 99% selectivity. • Enhanced visible light absorption by reducing band gap energy from 5.1 to 2.07 eV. • Controlled release of H adatoms from NaBH 4 maintained charge gradient across ETCs. • Direct atm. CO 2 conversion required 3.93 × 10 -4 Einsteins L -1 s -1 photonic intensity.