Cellulose‐Phytic Acid Composite Complexed Ru Catalyst for CO2 Hydrogenation to Free Formic Acid

The CO2 hydrogenation to free formic acid is an interesting topic, and low‐cost and high‐performance catalysts are highly desirable. This work presents a simple and green strategy to prepare high‐performance Ru catalysts for CO2 hydrogenation using cellulose and phytic acid composite (CPC) as support to complex with Ru(III). The CPC support prepared with assistance of 1‐butyl‐3‐methyl imidazolium chloride exhibits porous structure with abundant free −OH and −PO4 groups that can complex with Ru(III). The CPC complexed Ru catalyst (e. g., CPC‐Ru‐1) showed much higher activity for CO2 hydrogenation to formic acid in 1‐butyl‐3‐methyl imidazolium acetate than the reported heterogeneous Ru catalysts. Especially, CPC‐Ru‐1 with 0.094 wt% Ru afforded formic acid in selectivity >99 % with a turnover number around 1.8×104 and an initial production rate of 15.21 mol ⋅ g−1 ⋅ h−1 within the first 2 h at 120 °C. This catalyst is recyclable and stable without obvious activity loss after 5 runs. Formic acid through CO2 hydrogenation: A simple and green strategy is presented to prepare cellulose‐phytic acid composite complexed Ru catalyst, which shows high‐performance for CO2 hydrogenation in 1‐butyl‐3‐methyl imidazolium acetate, affording formic acid in selectivity >99 % with a high TON approaching 1.8×104.