Electrochemical CO2 reduction reaction (CO2RR) yielding value-added chemicals provides a sustainable approach for renewable energy storage and conversion. Bismuth-based catalysts prove to be promising candidates for converting CO2 and water into formate but still suffer from poor selectivity and activity and/or sluggish kinetics. Here, we report that ultrathin porous Bi nanosheets (Bi-PNS) can be prepared through a controlled solvothermal protocol. Compared with smooth Bi nanoparticles (Bi-NPs), the ultrathin, rough, and porous Bi-PNS provide more active sites with higher intrinsic reactivities for CO2RR. Moreover, such high activity further increases the local pH in the vicinity of the catalyst surfaces during electrolysis and thus suppresses the competing hydrogen evolution reaction. As a result, the Bi-PNS exhibit significantly boosted CO2RR properties, showing a Faradaic efficiency of 95% with an effective current density of 45 mA cm–2 for formate evolution at the potential of −1.0 V versus reversible hydrogen electrode.

The oxygen-groups on carbon supports are of vital importance for the synthesis and electrocatalytic carbon dioxide reduction performances of Bi nanoparticles.

The electrocatalytic properties of metal nanoparticles (NPs) strongly depend on their compositions and structures. Rational design of alloys and/or heterostructures provides additional approaches to modifying their surface geometric and electronic structures for optimized electrocatalytic performance. Here, a solution synthesis of freestanding intermetallic Au 2 Bi NPs, the heterostructures of Au 2 Bi/Bi hetero-NPs, and their promoted electrocatalytic CO 2 reduction reaction (CO 2 RR) performances were reported. It was revealed that the formation and in-situ conversion of heterogeneous seeds (e. g., Au) were of vital importance for the formation of intermetallic Au 2 Bi and Au 2 Bi/Bi hetero-NPs. It was also found that the Au components would act as the structure promoter moderating the binding strength for key intermediates on Bi surfaces. The alloying of Bi with Au and the formation of heterogeneous Au 2 Bi/Bi interfaces would create more surface active sites with modulated electronic structures and stronger adsorption strengths for key intermediates, promoting the CO 2 -to-HCOOH conversion with high activity and selectivity. This work presents a novel route for preparing intermetallic nanomaterials with modulated surface geometric/electric structures and promoting their electrocatalytic activities with alloying effects and interfacial effects. Such strategy may find wide application in catalyst design and synthesis for more electrocatalytic reactions.

CO 2 reduction reactions (CO 2 RR) powered by renewable electricity can directly convert CO 2 to hydrocarbons and fix the sustainable but intermittent energy (e. g., sunlight, wind, etc.) in stable and portable chemical fuels. Advanced catalysts boosting CO 2 RR with high activity, selectivity, and durability at low overpotentials are of great importance but still elusive. Here, we report that the ultrathin Pd-Ag dendritic nanoplates (PdAg DNPs) exhibited boosted activity, selectivity, and stability for producing formate from CO 2 at a very low overpotential in aqueous solutions under ambient conditions. As a result, the PdAg DNPs exhibited a Faradaic efficiency (FE) for formate of 91% and a cathodic energy efficiency (EE) of ~90% at the potential of À 0.2 V versus reversible hydrogen electrode (vs. RHE), showing significantly enhanced durability as compared with pure Pd catalysts. Our strategy represents a rational catalyst design by engineering the surface geometrical and electronic structures of metal nanocrystals and may find more applicability in future electrocatalysis.

The local surface plasmon resonance (LSPR) modulation represents a promising way for enhancing the upconversion photoluminescence (UCPL). The study on the coupling mechanism of LSPR and UCPL is of great...