Improving the selectivity and retaining the efficiency of catalysts are essential for industrial processes and remain a great challenge. Herein, we developed a facile route to synthesize Pd nanocubes (NCs) using Eosin Y as the photosensitizer under visible light. Subsequently, Pd NCs were uniformly loaded on N-doped carbon nanofibrous microspheres (NCMs) from carbonated chitin microspheres. This Pd NCs@NCM exhibited high reactivity and selectivity in alkyne semihydrogenation. For example, the hydrogenations of phenylacetylene to styrene and of 3-phenyl-2-propyn-1-ol to (Z)-cinnamyl alcohol were 12.9 and 18.3 times faster with Pd NCs@NCM than with Lindlar catalyst. According to the Mott–Schottky effect, loading of Pd NCs on N-doped carbon constructed a rectifying contact and decreased the electron density of Pd NCs. Density functional theory (DFT) calculations suggested that the high concentration of holes doped in Pd NCs weakened the interaction of alkenes on the Pd (100) facet and prevented further hydrogenation for a long time; this period of durable time is very helpful in chemical manufacturing. Thus, Pd NCs@NCM maintained both high reactivity and selectivity in comparison with surface-modified catalysts. This work provides an alternative strategy to design Mott–Schottky catalysts for selective hydrogenation reactions.

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Oxidative carbonylation using carbon monoxide has evolved as an attractive tool to valuable carbonyl-containing compounds, while mixing CO with a stoichiometric amount of a chemical oxidant especially oxygen is hazardous and limits its application in scale-up synthesis. By employing anodic oxidation, we developed an electrochemical palladium-catalyzed oxidative carbonylation of arylhydrazines with alkynes, which is regarded as an alternative supplement of the carbonylative Sonogashira reaction. Combining an undivided cell with constant current mode, oxygen-free conditions avoids the explosion hazard of CO. A diversity of ynones are efficiently obtained using accessible arylhydrazines and alkynes under copper-free conditions. A possible mechanism of the electrochemical Pd(0)/Pd­(II) cycle is rationalized based upon cyclic voltammetry, kinetic studies, and intermediates experiments.

Tertiary phosphines (III) find widespread use in many aspects of synthetic organic chemistry. Herein, we developed a facile and novel electrochemical oxidative N-H/P-H cross-coupling method, leading to a series of...

1,4-Dicarbonyl compounds are versatile scaffolds for the heterocycle synthesis, including the Paal–Knorr reaction. Herein, a feasible electrosynthesis method to access 1,4-dicarbonyl compounds has been developed from simple alkynes and 1,3-dicarbonyl compounds. When the undivided cell is combined with the constant current mode, aryl alkynes containing numerous medicinal motifs with 1,3-dicarbonyl esters or ketones react smoothly. External oxidant and catalyst-free conditions conform to the requirements of green synthesis.