Single-phase perovskite oxide with super-exchange induced atomic-scale synergistic active centers enables ultrafast hydrogen evolution

Abstract

The state-of-the-art active HER catalysts in acid media (e.g., Pt) generally lose considerable catalytic performance in alkaline media mainly due to the additional water dissociation step. To address this issue, synergistic hybrid catalysts are always designed by coupling them with metal (hydro)oxides. However, such hybrid systems usually suffer from long reaction path, high cost and complex preparation methods. Here, we discover a single-phase HER catalyst, SrTi0.7Ru0.3O3-δ (STRO) perovskite oxide highlighted with an unusual super-exchange effect, which exhibits excellent HER performance in alkaline media via atomic-scale synergistic active centers. With insights from first-principles calculations, the intrinsically synergistic interplays between multiple active centers in STRO are uncovered to accurately catalyze different elementary steps of alkaline HER; namely, the Ti sites facilitates nearly-barrierless water dissociation, Ru sites function favorably for OH* desorption, and non-metal oxygen sites (i.e., oxygen vacancies/lattice oxygen) promotes optimal H* adsorption and H2 desorption.

A General Strategy to Boost Electrocatalytic Nitrogen Reduction on Perovskite Oxides via the Oxygen Vacancies Derived from A‐Site Deficiency

“…However, this process not only operates under harsh environments involving high temperatures (400-500 °C) and activities toward NRR and others (e.g., oxygen evolution, hydrogen evolution) of perovskite oxides can be effectively enhanced through oxygen vacancy engineering. [20][21][22][23][24][25][26] The main mechanism has been certified to be that B-site cations combining with their adjacent oxygen vacancies can serve as unsaturated active centers that strengthen the ability to adsorb/ activate N 2 molecule and thus lead NRR on the optimal reaction pathway. [14] Despite these efforts, their preparation methods involving special atmosphere (e.g., 5% H 2 /Ar) annealing had made it challenging to rationally tailor the oxygen vacancies, not mentioning the instability of most of the perovskite oxides under those conditions.…”

Rational Construction of Ruthenium‐Cobalt Oxides Heterostructure in ZIFs‐Derived Double‐Shelled Hollow Polyhedrons for Efficient Hydrogen Evolution Reaction

“…The negative free energy demonstrates the exothermic HER pathway for hetero-RuO 2 /Co 3 O 4 , indicating that the reaction step on this catalyst is thermodynamically favorable. [47] In alkaline media, the adsorbed hydrogen (*H) comes from the dissociation of H 2 O molecules, which means that the adsorption and activation of H 2 O are critical to the overall HER performance. [48,49] As seen in Figure 5A, the hetero-RuO 2 /Co 3 O 4 displays preponderant H 2 O adsorption and dissociation free energy (−0.75, −1.21 eV) than those of RuO 2 (0.45, 0.29 eV) and Co 3 O 4 (0.91, 1.11 eV).…”

New TiO2‐Based Oxide for Catalyzing Alkaline Hydrogen Evolution Reaction with Noble Metal‐Like Performance

“…Hydrogen has been considered as an ideal and sustainable energy for the future due to its carbon‐free nature and the highest gravimetric energy density. [ 1–5 ] Alkaline water electrolysis is one of the most promising ways for hydrogen production which generated by cathodic hydrogen evolution reaction (HER). [ 6–10 ] To achieve high efficiency of hydrogen production, efficient electrocatalysts are urgently demanded to accelerate HER kinetics.…”

“…[ 11–14 ] Generally, the HER activity is governed by three important factors, i.e., H* adsorption on the catalyst surface, the kinetic barrier of water dissociation, and the poisoning effect of hydroxyl on active sites. [ 3,5,6 ] Pt‐based metals and alloys are the benchmark HER electrocatalysts in alkaline solutions, showing high electrocatalytic activity due to ideal intermediate energy barriers, but formidable cost and poor durability intensely inhibits their practical application. [ 15–17 ] Thus, it remains a huge challenge to develop efficient and inexpensive alternatives to Pt‐based electrocatalysts for HER, in particular for operation in alkaline solution.…”