Effects of strain, pH and oxygen-deficient on catalytic performance of Ruddlesden-Popper oxide Srn+1RunO3n+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 Sr 2 RuO 4 , Sr 3 Ru 2 O 7 and Sr 3 Ru 2 O 6 were comprehensively calculated for the first time. Our results confirm that oxygen-deficient R–P Sr 3 Ru 2 O 6 is beneficial for its catalytic performance in alkaline environments. Ranking of catalytic performance in acidic environments: Sr 2 RuO 4 >Sr 3 Ru 2 O 6 >Sr 3 Ru 2 O 7 , relatively in alkaline environments: Sr 3 Ru 2 O 6 >Sr 3 Ru 2 O 7 >Sr 2 RuO 4 , which means pH actually affects the performance of R–P structure catalysts. In other words, acidic environments are conducive to the catalytic activity of Sr 2 RuO 4 , while alkaline environments are beneficial for Sr 3 Ru 2 O 6 and Sr 3 Ru 2 O 7. 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 Sr 3 Ru 2 O 6. 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. • Firstly calculated HER catalytic activity of R–P structure Sr 3 Ru 2 O 6 and Sr 3 Ru 2 O 7. • Oxygen-deficient of Sr 3 Ru 2 O 6 benefices the catalytic performance in alkaline solution. • Catalysis in acid: Sr 2 RuO 4 >Sr 3 Ru 2 O 6 >Sr 3 Ru 2 O 7 , alkaline: Sr 3 Ru 2 O 6 >Sr 3 Ru 2 O 7 >Sr 2 RuO 4. • Conducive to catalysis: acidity for Sr 2 RuO 4 , alkalinity for Sr 3 Ru 2 O 6 & Sr 3 Ru 2 O 7. • 1% & 3% tensile strain can further enhance the HER catalytic performance of Sr 3 Ru 2 O 6. [ABSTRACT FROM AUTHOR]