Achieving efficient almost CO-free hydrogen production from methanol steam reforming on Cu modified α-MoC

Abstract

Methanol, serving as a hydrogen carrier, is utilized for hydrogen production through steam reforming, a promising technology for on-vehicle hydrogen applications. Despite the impressive performance of noble-metal catalysts in hydrogen generation, the development of highly efficient non-noble-metal heterogeneous catalysts remains a formidable challenge. In our investigation, we systematically controlled the influence of the MoC phase on the dispersion of active copper metal to enhance the catalytic performance of methanol steam reforming (MSR). Within the Cu/MoC catalyst systems, featuring MoC phases including α-MoC_1−x and Mo₂C phases, alongside MoO₂ phases, the Cu/α-MoC catalyst exhibited exceptional catalytic efficacy at 350 °C. It achieved a remarkable hydrogen selectivity of up to 80% and an outstanding CO selectivity of 0. Notably, its hydrogen production rate reached 44.07 mmol g_cat⁻¹ h⁻¹, surpassing that of Cu/Mo₂C (37.05 mmol g_cat⁻¹ h⁻¹), Cu/MoO₂ (19.02 mmol g_cat⁻¹ h⁻¹), and commercial CuZnAl (38 mmol g_cat⁻¹ h⁻¹) catalysts. Additionally, we introduced the concept of the (Cu₁–Cu_n)/α-MoC catalyst, wherein Cu atoms are immobilized on the α-MoC surface, facilitating the coexistence of isolated Cu atoms (Cu₁) and subnanometer copper cluster (Cu_n) species at a high dispersibility. This innovative design capitalizes on the robust interaction between the α-MoC_1−x phase and the Cu active center, yielding a substantial augmentation in the catalytic activity.