Effects of strain, pH and oxygen-deficient on catalytic performance of Ruddlesden-Popper oxide Sr n+1 Ru n O 3n+1 (n=1, 2) for hydrogen evolution reaction

Due to low content of precious metals and good stability, Ruddlesden-Popper (R-P) structure oxides are considered as promising hydrogen evolution reaction (HER) catalysts. However, related research is scarce, hindering its further improvement. In this paper, effects of strain, pH, oxygen-deficient and layer numbers on HER catalytic performance of R-P structure oxides Sr2RuO4, Sr3Ru2O7 and Sr3Ru2O6 were comprehensively calculated for the first time. Our results confirm that oxygen-deficient R-P Sr3Ru2O6 is beneficial for its catalytic performance in alkaline environments. Ranking of catalytic performance in acidic environments: Sr2RuO4>Sr3Ru2O6>Sr3Ru2O7, relatively in alkaline environments: Sr3Ru2O6>Sr3Ru2O7>Sr2RuO4, which means pH actually affects the performance of R-P structure catalysts. In other words, acidic environments are conducive to the catalytic activity of Sr2RuO4, while alkaline environments are beneficial for Sr3Ru2O6 and Sr3Ru2O7. We also calculated the effects of tensile and compressive strains and found that 1% and 3% tensile strain can further enhance the HER catalytic performance of Sr3Ru2O6. Taking into account various practical factors, our work investigated the HER catalytic mechanism of R-P oxides, providing theoretical guidance for the development of R-P structure catalysts.