Fullerene on non-iron cluster-matrix co-catalysts promotes collaborative H2 and N2 activation for ammonia synthesis

Abstract

Developing highly effective catalysts for ammonia (NH₃) synthesis is a challenging task. Even the current, prevalent iron-derived catalysts used for industrial NH₃ synthesis require harsh reaction conditions and involve massive energy consumption. Here we show that anchoring buckminsterfullerene (C₆₀) onto non-iron transition metals yields cluster-matrix co-catalysts that are highly efficient for NH₃ synthesis. Such co-catalysts feature separate catalytic active sites for hydrogen and nitrogen. The 'electron buffer' behaviour of C₆₀ balances the electron density at catalytic transition metal sites and enables the synergistic activation of nitrogen on transition metals in addition to the activation and migration of hydrogen on C₆₀ sites. As demonstrated in long-term, continuous runs, the C₆₀-promoting transition metal co-catalysts exhibit higher NH₃ synthesis rates than catalysts without C₆₀. With the involvement of C₆₀, the rate-determining step in the cluster-matrix co-catalysis is found to be the hydrogenation of *NH₂. C₆₀ incorporation exemplifies a practical approach for solving hydrogen poisoning on a wide variety of oxide-supported Ru catalysts.