Selective hydrogenation of p-chloronitrobenzene on nanosized gold clusters: A theoretical study

Highlights: • Hydrogenation processes of p-CNB on Au₁₃ and Au₅₅ are compared with Au₂₀ nanocluster. • The adsorption energy of all species exhibit the following trend: Au₁₃ > Au₂₀ > Au₅₅. • Au₅₅ nanocluster has the least hydrogenation reaction barrier of the rate-limiting step. • The dechlorination reaction barrier on Au₅₅ is higher than that on Au₁₃ and Au₂₀ nanoclusters. The selective hydrogenation of p-chloronitrobenzene on Au₁₃ and Au₅₅ nanoclusters has been systematically studied by density functional theory (DFT), allowing for a comparison with Au₂₀ nanocluster. All possible adsorption configurations of relevant intermediates are identified. The adsorption energy of all species exhibit the following trend: Au₁₃ > Au₂₀ > Au₅₅. The detailed reaction barriers show that Au₅₅ nanocluster has the least hydrogenation reaction barrier of the rate-limiting step, whereas the dechlorination reaction is least likely to cause on Au₅₅ nanocluster. These observations suggest that the 55-atom gold cluster is predicated to be the appropriate catalyst for practical application.