Formic acid (FA) is a promising hydrogen storage carrier for high power density hydrogen fuel cells. However, dehydrogenation of FA usually produces CO by-products that poison the catalyst. The prevention of FA decomposition into CO within high-temperature proton exchange membrane (HT-PEM) systems operating at 130–200°C remains a formidable scientific challenge. Here, we propose a Ni doping-induced active phase transition of molybdenum carbide on carbon-based catalysts, enhancing hydrogen production from FA. Ni-MoC/NC achieves complete FA conversion at 190 °C, maintaining stable catalytic performance over 170 hours. In MoC/NC, Mo primarily exists as β-Mo 2 C and γ-Mo 2 N, while in Ni-MoC/NC, it predominantly forms α-MoC and γ-Mo 2 N. XRD and XPS analyses reveal that Ni doping induces the transformation of β-Mo 2 C into α-MoC, improving catalytic performance. Mechanistic studies identify HCOO* as a key intermediate in FA dehydrogenation on Ni-MoC/NC. The catalyst promotes the dissociation of HCOOH* into HCOO*, reduces the energy barrier for HCOO* conversion to CO 2 *, and inhibits CO by-product formation, accelerating FA dehydrogenation. These findings highlight Ni-MoC/NC as a robust catalyst for efficient hydrogen production. • Ni-promoted Mo-soybean solid-phase reaction converts β-Mo 2 C to α-MoC. • Catalyst gives 100% FA conversion and H 2 selectivity; 170 h at 190 °C. • Reveals functional group evolution and intermediate formation in FA dehydrogenation.
Fu et al. (Sun,) studied this question.