Tuning the CO2 hydrogenation path by moderately phosphating the Co-Al catalyst toward methanol synthesis

Regulating diversified reaction paths is one of the key challenges for commercial CO2 hydrogenation. Herein, a phosphating strategy is proposed to modify the surface structure of a layered double hydroxide-derived Co-Al catalyst for CO2 hydrogenation to CH3OH. It is shown that moderate phosphating can achieve a uniform incorporation of P without damaging the original layered morphology and crystal structure. Experiments and density functional theory calculations demonstrate that a significant electron transfer occurs in the surface oxygen vacancies after phosphating, which promotes the direct hydrogenation of key intermediate H3CO* to CH3OH by constraining the cleavage of the C-O bond in H3CO*. The CH3OH selectivity and space-time yield are, therefore, substantially boosted after moderate phosphating, far superior to those on conventional Cu-, In2O3- and noble metal-based catalysts. This work provides valuable insights into the manipulation of reaction paths through the design and rational modification of catalytic materials.