Abstract
Metal promotion is the most widely adopted strategy for enhancing the hydrogenation functionality of an oxide catalyst. Typically, metal nanoparticles or dopants are located directly on the catalyst surface to create interfacial synergy with active sites on the oxide, but the enhancement effect may be compromised by insufficient hydrogen delivery to these sites. Here, we introduce a strategy to promote a ZnZrO(x) methanol synthesis catalyst by incorporating hydrogen activation and delivery functions through optimized integration of ZnZrO(x) and Pd supported on carbon nanotube (Pd/CNT). The CNT in the Pd/CNT + ZnZrO(x) system delivers hydrogen activated on Pd to a broad area on the ZnZrO(x) surface, with an enhancement factor of 10 compared to the conventional Pd-promoted ZnZrO(x) catalyst, which only transfers hydrogen to Pd-adjacent sites. In CO(2) hydrogenation to methanol, Pd/CNT + ZnZrO(x) exhibits drastically boosted activity-the highest among reported ZnZrO(x)-based catalysts-and excellent stability over 600 h on stream test, showing potential for practical implementation.