Br, O-Modified Cu(111) Interface Promotes CO2 Reduction to Multicarbon Products.

Electrochemical reduction of CO2 to multicarbon (C2+) products with added value represents a promising strategy for achieving a carbon-neutral economy. Precise manipulation of the catalytic interface is imperative to control the catalytic selectivity, particularly toward C2+ products. In this study, a unique Cu/UIO-Br interface is designed, wherein the Cu(111) plane is co-modified simultaneously by Br and O from UIO-66-Br support. Such Cu/UIO-Br catalytic interface demonstrates a superior Faradaic efficiency of ≈53% for C2+ products (ethanol/ethylene) and the C2+ partial current density reached 24.3 mA cm-2 in an H-cell electrolyzer. The kinetic isotopic effect test, in situ attenuated total reflection Fourier transform infrared spectroscopy and density functional theory calculations have been conducted to elucidate the catalytic mechanism. The Br, O co-modification on the Cu(111) interface enhanced the adsorption of CO2 species. The hydrogen-bond effect from the doped Br atom regulated the kinetic processes of *H species in CO2RR and promoted the formation of *COH intermediate. The formed *COH facilitates the *CO-*COH coupling and promotes the C2+ selectivity finally. This comprehensive investigation not only provides an in-depth study and understanding of the catalytic process but also offers a promising strategy for designing efficient Cu-based catalysts with exceptional C2+ products.

Quantifying Interfacial Bonding Using Thermal Boundary Conductance at Cubic Boron Nitride/Copper Interfaces with a Large Mismatch of Phonon Density of States.

Interfacial bonding that directly influences the functional and mechanical properties of metal/nonmetal composites is commonly estimated by destructive pull-off measurements such as scratch tests, etc. However, these destructive methods may not be applicable under certain extreme environments; it is urgently necessary to develop a nondestructive quantification technique to determine the composite's performance. In this work, the time-domain thermoreflectance (TDTR) technique is applied to study the inter-relationship between interfacial bonding and interface characteristics through thermal boundary conductance (G) measurements. We think that interfacial phonon transmission capability plays a decisive role in influencing interfacial heat transport, especially for scenarios with a large mismatch of phonon density of states (PDOS). Moreover, we demonstrated this method at (100) and (111) cubic boron nitride/copper (c-BN/Cu) interfaces by both experimental and simulation efforts. The results show that the TDTR-measured G of the (100) c-BN/Cu interface (30 MW/m2·K) is about 20% higher than that of the (111) c-BN/Cu (25 MW/m2·K), which is ascribed to that higher interfacial bonding of the (100) c-BN/Cu endows it with better interfacial phonon transmission capability. In addition, detailed comparison of 10+ other metal/nonmetal interfaces exhibits similar positive relationship for interfaces with a large PDOS mismatch but negative relationship for interfaces with a small PDOS mismatch. The latter one is attributed to that extra inelastic phonon scattering and electron transport channels abnormally promoting interfacial heat transport. This work may provide some insights into quantitatively establishing inter-relationship between interfacial bonding and interface characteristics.