Efficient electroreduction of CO 2 to multi-carbon products is a challenging reaction because of the high energy barriers for CO 2 activation and CC coupling, which can be tuned by designing the metal centers and coordination environments of catalysts. Here, we design single atom copper encapsulated on N-doped porous carbon (Cu-SA/NPC) catalysts for reducing CO 2 to multi-carbon products. Acetone is identified as the major product with a Faradaic efficiency of 36.7% and a production rate of 336.1 μg h −1. Density functional theory (DFT) calculations reveal that the coordination of Cu with four pyrrole-N atoms is the main active site and reduces the reaction free energies required for CO 2 activation and CC coupling. The energetically favorable pathways for CH 3 COCH 3 production from CO 2 reduction are proposed and the origin of selective acetone formation on Cu-SA/NPC is clarified. This work provides insight into the rational design of efficient electrocatalysts for reducing CO 2 to multi-carbon products.

Electrocatalytic conversion of nitrogen oxides to value-added chemicals is a promising strategy for mitigating the human-caused unbalance of the global nitrogen-cycle, but controlling product selectivity remains a great challenge. Here we show iron–nitrogen-doped carbon as an efficient and durable electrocatalyst for selective nitric oxide reduction into hydroxylamine. Using in operando spectroscopic techniques, the catalytic site is identified as isolated ferrous moieties, at which the rate for hydroxylamine production increases in a super-Nernstian way upon pH decrease. Computational multiscale modelling attributes the origin of unconventional pH dependence to the redox active (non-innocent) property of NO. This makes the rate-limiting NO adsorbate state more sensitive to surface charge which varies with the pH-dependent overpotential. Guided by these fundamental insights, we achieve a Faradaic efficiency of 71% and an unprecedented production rate of 215 μmol cm−2 h−1 at a short-circuit mode in a flow-type fuel cell without significant catalytic deactivation over 50 h operation.

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As eries of heteroleptic iridium(III) complexes functionalized with two phosphonic acid (ÀPO 3 H 2 )g roups ( dfppy IrP, ppy IrP, btp IrP,a nd piq IrP)w ere prepared and anchored onto rhenium(I) catalyst( ReP)-loadedT iO 2 particles (TiO 2 / ReP) to build up an ew IrP-sensitized TiO 2 photocatalyst system (IrP/TiO 2 /ReP). The photosensitizing behavior of the IrP series was examined within the IrP/TiO 2 /ReP platform for the photocatalytic conversion of CO 2 into CO. The four IrPbased ternary hybridss howed increased conversion activity and durability than that of the corresponding homo-(IrP + ReP) and heterogeneous (IrP + TiO 2 /ReP) mixed systems.Amongt he four IrP/TiO 2 /ReP photocatalysts, the lowenergy-light (> 500 nm) activated piq IrP immobilized ternary system ( piq IrP/TiO 2 /ReP) exhibitedt he most durable conversion activity,g iving at urnover number of ! 730 for 170 h. A similark inetic feature observed through time-resolved photoluminescence measurements of both btp IrP/TiO 2 and TiO 2free btp IrP films suggestst hat the net electron flow in the ternary hybrid proceeds dominantly through ar eductive quenching mechanism,u nlike the oxidative quenching route of typical dye/TiO 2 -based photolysis.[a] P.Scheme1.Schematicrepresentation of the photocatalytic IrP/TiO 2 /ReP ternary system and components used in this study.TON = turnovern umber, NP = nanoparticle.