Search for: All records

Abstract Doping gold nanoparticles within covalent organic frameworks (AuNPs@COFs) has garnered enormous momentum due to their unique properties and broad applications. Nevertheless, prevailing multi‐step synthesis is plagued with low time efficiency, eco‐unfriendliness, and tedious protocols. Herein, we introduce a rapid, sustainable, scalable, one‐step mechanochemical strategy for synthesizing up to four AuNPs‐doped COFs via steel ball milling within an hour under ambient conditions. This approach overcomes the synthetic barriers of conventional multi‐step solution‐based methods, such as extended reaction times (5 days), milligram scale, the use of toxic solvents, elevated temperatures, and reliance on external reducing agents. One exemplary AuNPs@COF (AuNPs@DMTP‐TPB) exhibits high crystallinity, porosity, small AuNP size, and uniform dispersion (5.4±0.6 nm), surpassing its counterpart synthesized via multi‐step solution‐based methods (6.4±1.1 nm). Notably, the gram‐scale synthesis of AuNPs@DMTP‐TPB can be successfully achieved. Control experiments suggest that thein situformation of AuNPs is attributed to the galvanic reduction of gold precursor by stainless steel apparatus. As a proof‐of‐concept catalytic application, AuNPs@DMTP‐TPB demonstrates remarkable catalytic activity and recyclability for the aqueous reduction of 4‐nitrophenol under ambient conditions. This study provides an environmentally benign and fast pathway to synthesize AuNPs@COFs via mechanochemistry for the first time, opening tremendous possibilities for heterogeneous catalysis and beyond. 

To address a long‐existing debate on what copper species are responsible for efficient CC coupling, especially ethanol formation, in electrochemical CO₂reduction reaction, herein, a comprehensive study using Cu₃N nanocubes with a uniform size and shape, alongside a single crystalline phase is reported. The Cu₃N nanoensemble electrode has a remarkable Faradaic efficiency (FE) of 64% for ethanol production at a relatively low potential of −0.6 V versus reversible hydrogen electrode. Throughin‐operandoX‐ray absorption spectroscopy study, a dynamic phase evolution that directly correlates with changes in FE across varying applied potentials is observed. Notably, the nanoensemble with a composition of ≈71% Cu⁺and 29% Cu⁰is identified as being selective for ethanol formation at the low overpotential. Conversely, a predominantly metallic Cu phase formed at potentials more negative than −0.6 V favors the hydrogen evolution reaction. Density functional theory calculations at the Cu₃N–Cu interface substantiate that the coexistence of Cu⁰–Cu⁺not only energetically favors the ethanol reaction pathway but also destabilizes the intermediates for ethylene pathway.