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 ZnZrOx methanol synthesis catalyst by incorporating hydrogen activation and delivery functions through optimized integration of ZnZrOx and Pd supported on carbon nanotube (Pd/CNT). The CNT in the Pd/CNT + ZnZrOx system delivers hydrogen activated on Pd to a broad area on the ZnZrOx surface, with an enhancement factor of 10 compared to the conventional Pd-promoted ZnZrOx catalyst, which only transfers hydrogen to Pd-adjacent sites. In CO2 hydrogenation to methanol, Pd/CNT + ZnZrOx exhibits drastically boosted activity-the highest among reported ZnZrOx-based catalysts-and excellent stability over 600 h on stream test, showing potential for practical implementation. Boosting activity of oxide catalysts is a long-lasting challenge to developing efficient catalysts for industrially important reactions such as CO2-to-methanol. Here, the authors report a strategy for enhancing the activity of a ZnZrOx methanol synthesis catalyst via engineered nanoscale H supply.