Crystalline catalyst-mediated microenvironment engineering boosting CO2 electroreduction to dimethyl carbonate

Electrochemically converting CO 2 and CH 3 OH into dimethyl carbonate (DMC) is highly desirable but challenging, as it necessitates the catalysts’ simultaneous adsorption and activation of CO 2 and CH 3 OH. Besides, a moderately dense distribution of CO 2 catalytic active site is conductive to facilitating the C–O coupling. To solve these challenges, a nano-sized polyoxometalate (POM), [{Cu 6 (μ 3 -OH) 3 (en) 3 (H 2 O) 3 }(B-α-PW 9 O 34 )]·7 H 2 O ({Cu 6 PW 9 }, en = ethylenediamine), featuring ordered {Cu 6 } cluster and {PW 9 } intervals, is synthesized for electro-production of DMC. Benefiting from the unique architecture, the pre-prepared {Cu 6 PW 9 }/Cu FA catalyst exhibits a favorable DMC yield of 2.4 mol L –1 h –1 and 83.0 % Faradaic efficiency (FE) at room temperature (–1.6 V vs. Ag/AgCl). It is also capable of exerting the catalytic activity at –15 °C. Experimental investigations illustrate that the entire {Cu 6 PW 9 } provides a negatively charged environment to adsorb alkali metal cations (AM) as a cocatalyst to assist both the adsorption and activation of the CO 2 and CH 3 OH reactants. The ordered and discrete active sites coupling with the fixed metal–metal (M–M) distance of the skeleton effectively facilitate the coupling of *CO and *OCH 3 to DMC. This study presents a crystallography-dependent catalyst design strategy for efficient synthesis of DMC under ambient and low-temperature conditions. A nano-sized polyoxometalate featuring ordered {Cu 6 } cluster and {PW 9 } intervals is synthesized for the electro-production of DMC. The discrete and fixed Cu active sites, coupling with the anionic surface of polyoxometalate effectively facilitate the coupling of *CO and *OCH 3 to DMC. This study offers a crystallography-dependent catalyst design strategy for efficient synthesis of DMC. • A crystalline-mediated microenvironment engineering strategy to drive CO 2 into dimethyl carbonate (DMC). • The {Cu 6 PW 9 }/Cu FA could simultaneously adsorb and activate CO 2 and CH 3 OH. • The uniform and discrete Cu cluster promotes C–O coupling between *CO and *OCH 3 .