Methanation and photo-methanation of carbon dioxide at room temperature and atmospheric pressure

The Sabatier reaction: CO2+4H2 → CH4+2H2O(g) ΔG°298K = −27 kcal mol−1 (1) is an important catalytic process of wide industrial and academic interest1—3. It is applied to syngas conversion and the treatment of waste streams. Methane is one of the most important carbon resources of the world, serving as an energy vector as well as a feedstock for higher-value chemicals4—6. Despite its favourable thermodynamics, the eight-electron reduction of CO2 to CH4 by hydrogen is difficult to achieve: high-energy intermediates impose large kinetic barriers, and the formation of side products is common. Intensive investigations during the past decade have therefore been aimed at improving the activity and selectivity of methanation catalysts 1–3,8–11. Although significant progress has been made in this field, elevated temperatures (T>300 °C) and pressures (P> 1 atm) are still required for methane generation to proceed at significant rates and yields. Here we report the selective conversion of CO2 to methane at room temperature and atmospheric pressure, using highly dispersed Ru/RuOx loaded onto TiO2 as a catalyst. The reaction rate is sharply enhanced through photo-excitation of the support material.