DFT computational insight into the catalytic dehydrogenation of formic acid for H2 production over Cr-doped C20 fullerene: Cr-H active center and high selectivity mechanism.

The dehydrogenation of formic acid (HCOOH) to H2 offers a sustainable energy conversion route, yet developing efficient non-noble metal catalysts remains a critical challenge. Herein, density functional theory (DFT) calculations were performed to systematically investigate the catalytic performance of Cr-doped C20 fullerene (C19Cr) for HCOOH dehydrogenation. Our results show that the reaction follows an O-H bond-prior activation mechanism: the first HCOOH molecule dissociates to form a Cr-H hydride, which serves as the catalytically active center, and subsequent reaction with a second HCOOH molecule yields H2. The formation of the Cr-H hydride is identified as the rate-determining step, featuring a moderate barrier of 21.2 kcal mol-1, confirming kinetic feasibility under mild conditions. Notably, the undesired dehydration pathway (to H2O and CO) is kinetically and thermodynamically unfavorable compared to the target dehydrogenation pathway (to H2 and CO2), endowing C19Cr with high H2 selectivity. This work highlights the potential of Cr-doped fullerenes as non-noble metal catalysts for HCOOH dehydrogenation and provides valuable theoretical insights for the rational design of efficient H2 storage/utilization catalysts.