Computational screening of transition-metal atom embedding in 1T-TaS2 monolayer defects as efficient oxygen-reduction/evolution-reaction bifunctional catalysts

With the rapid development of global green energy and low-carbon economy, the development of high-performance, low-cost and stable catalysts for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is becoming more and more important. Herein, based on comprehensive density functional theory (DFT) computations, we explore the catalytic activity of metal-atom doped 1T-TaS₂ single-atom catalysts (SACs) TM@1T-TaS₂ for ORR and OER, where TM = V, Cr, Mn, Fe, Co, Ni, Cu, Nb, Mo, Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au. It is found that Pd@1T-TaS₂ can be an excellent bifunctional electrocatalyst with OER and ORR overpotentials (0.47 V/0.49 V) comparable to the noble metal catalysts. In view of the good catalytic activity of Pd@1T-TaS₂ , the 4-electron process stepwise hydrogenation reaction energy barrier was further calculated with a maximum barrier of 0.44 eV. Additionally, it has been elucidated through volcano curves evolved from the scaling relation of adsorption energy that the good catalytic activity stems from the moderate adsorption of oxygenated intermediates. Finally, d-band center and crystal orbital Hamiltonian populations methods were used to explain the catalytic origin. Suitable d-band centers lead to moderate adsorption strength, further implying good catalytic performances.