Vanadium phosphorus oxide (VPO) catalyst activation method is essential for the catalytic oxidation form n-butane to maleic anhydride. Here, we evaluate the effect of steam content on VPO catalyst during the activation process and validate the adjustment of the steam content could modulate the VPO activity. The DRIFTS results reveal that the steam content governs the formation of P-OH and V-OH species on the surface of VPO catalyst, whereas these sites would not enhance the catalytic activity directly. In contrast, the L acid site V⁵⁺-O-PO, forming a mutual transformation relationship with the P-OH species under steam/O₂ conditions, is the main active site that dominates the conversion of n-butane, and a moderate amount of steam plays a role in stabilizing the V⁵⁺-O-PO site.

钒磷氧化物（VPO）催化剂活化方法对于将正丁烷催化氧化为马来酸酐至关重要。在这里，我们评估了活化过程中蒸汽含量对 VPO 催化剂的影响，并验证了蒸汽含量的调整可以调节 VPO 活性。DRIFTS 结果表明，蒸汽含量控制着 VPO 催化剂表面 P-OH 和 V-OH 物质的形成，而这些位点不会直接提高催化活性。相比之下，在蒸汽/O ₂条件下，与 P-OH 物种形成相互转化关系的 L 酸性位点 V ⁵⁺ -OP O是主导n转化的主要活性位点。-丁烷和适量的蒸汽在稳定V ⁵⁺ -OP O 位点中起作用。