Mesoporous N-Doped Carbon-Confined PdNi Nanoclusters for Efficient and Robust Dehydrogenation of Additive-Free Formic Acid.

Abstract

Formic acid is a promising liquid organic hydrogen carrier, thanks to its high volumetric hydrogen storage density, easy storage and transport, and potential for regeneration from CO2. However, developing efficient, durable, and cost-effective catalysts for additive-free formic acid dehydrogenation (FAD) remains a considerable challenge. Herein, ultrafine PdNi nanoclusters (~1.5 nm) were successfully confined within amine-functionalized mesoporous N-doped carbon (AMNC) through a facile impregnation-reduction strategy. The resultant PdNi/AMNC exhibits exceptional catalytic performance for additive-free FAD, achieving complete FA conversion and 100% H2 selectivity across a temperature range from 303 to 333 K. At 323 K, the catalyst demonstrates a high initial turnover frequency of 5751 h-1. Remarkably, it maintains quantitative conversion and perfect H2 selectivity over 20 consecutive reaction cycles, highlighting its superior stability compared to most reported systems. The high catalytic activity primarily stems from the formation of electron-enriched PdNi nanoclusters, driven by the strong electronic metal-support interaction between PdNi and AMNC, as well as electronic coupling between Pd and Ni. Isotope experiments confirmed that the dissociation of CH bond in FA is more difficult than that of OH bond on PdNi/AMNC catalyst in FAD. This work offers a practical design strategy for constructing high-performance bimetallic nanocatalysts for sustainable hydrogen production.