The electrocatalytic CO2 reduction reaction (CRR) and N2 reduction reaction (NRR), which convert inert small molecules into high-value products under mild conditions, have received much research attention.

Identification of catalytic sites for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in carbon materials remains a great challenge. Here, we construct a pyridinic-N-dominated doped graphene with abundant vacancy defects. The optimized sample with an ultrahigh pore volume (3.43 cm3 g–1) exhibits unprecedented ORR activity with a half-wave potential of 0.85 V in alkaline. For the first time, density functional theory results indicate that the quadri-pyridinic N-doped carbon site synergized with a vacancy defect is the active site, which presents the lowest overpotential of 0.28 V for ORR and 0.28 V for OER. The primary Zn–air batteries display a maximum power density of 115.2 mW cm–2 and an energy density as high as 872.3 Wh kg–1. The rechargeable Zn–air batteries illustrate a low discharge–charge overpotential and high stability (>78 h). This work provides new insight into the correlation between the N configuration synergized with a vacancy defect in electrocatalysis.

Two-phase or multiphase compounds have been evidenced to exhibit good electrochemical performance for energy applications; however, the mechanism insights into these materials, especially the performance improvement by engineering the high-active phase boundaries in bimetallic compounds, remain to be seen. Here, we report a bimetallic selenide heterostructure (CoSe 2 /ZnSe) and the fundamental mechanism behind their superior electrochemical performance. The charge redistribution at the phase boundaries of CoSe 2 /ZnSe was experimentally and theoretically proven. Benefiting from the abundant phase boundaries, CoSe 2 /ZnSe exerts low Na + adsorption energy and fast diffusion kinetics for sodium-ion batteries and high activity for oxygen evolution reaction. As expected, excellent sodium storage capability, specifically a superb cyclic stability of up to 800 cycles for the Na 3 V 2 (PO 4 ) 3 ∥CoZn-Se full cell, and efficient water oxidation with a small overpotential of 320 mV to reach 10 mA cm −2 were obtained. This work demonstrates the importance of phase boundaries in bimetallic compounds to boost the performance in various fields.

It is highly desirable but challenging to optimize the structure of photocatalysts at the atomic scale to facilitate the separation of electron–hole pairs for enhanced performance. Now, a highly efficient photocatalyst is formed by assembling single Pt atoms on a defective TiO2 support (Pt1/def‐TiO2). Apart from being proton reduction sites, single Pt atoms promote the neighboring TiO2 units to generate surface oxygen vacancies and form a Pt‐O‐Ti3+ atomic interface. Experimental results and density functional theory calculations demonstrate that the Pt‐O‐Ti3+ atomic interface effectively facilitates photogenerated electrons to transfer from Ti3+ defective sites to single Pt atoms, thereby enhancing the separation of electron–hole pairs. This unique structure makes Pt1/def‐TiO2 exhibit a record‐level photocatalytic hydrogen production performance with an unexpectedly high turnover frequency of 51423 h−1, exceeding the Pt nanoparticle supported TiO2 catalyst by a factor of 591.

3d transition metals or their derivatives encapsulated in nitrogen-doped nanocarbon show promising potential in non-precious metal oxygen electrocatalysts.

Focusing on the atomic-scale engineering of CVD grown 2D TMDs, we discuss the six engineering strategies to tailor the electronic structure, conductivity and electrocatalytic properties in detail. Finally, challenges and perspectives are addressed.

Quasi-solid-state Zn-air batteries are usually limited to relatively low-rate ability (<10 mA cm−2), which is caused in part by sluggish oxygen electrocatalysis and unstable electrochemical interfaces. Here we present a high-rate and robust quasi-solid-state Zn-air battery enabled by atomically dispersed cobalt sites anchored on wrinkled nitrogen doped graphene as the air cathode and a polyacrylamide organohydrogel electrolyte with its hydrogen-bond network modified by the addition of dimethyl sulfoxide. This design enables a cycling current density of 100 mA cm−2 over 50 h at 25 °C. A low-temperature cycling stability of over 300 h (at 0.5 mA cm−2) with over 90% capacity retention at −60 °C and a broad temperature adaptability (−60 to 60 °C) are also demonstrated.

Due to the earth abundance and tunable electronic properties, etc., transition metal oxides (TMOs) show attractive attention in oxygen evolution reaction. O‐vacancies (Vo) play important roles in tailoring the local surface and electronic environment to lower the activation barriers. Herein, an effective strategy is shown to enhance the oxygen evolution reduction (OER) performance on Co3O4 ultrathin nanosheets via combined cation substitution and anion vacancies. The oxygen‐deficient Fe‐Co‐O nanosheets (3–4 nm thickness) display an overpotential of 260 mV@10 mA cm−2 and a Tafel slope of 53 mV dec−1, outperforming those of the benchmark RuO2 in 1.0 m KOH. Further calculations demonstrate that the combined introduction of Fe cation and Vo with appropriate location and content finely tune the intermediate absorption, consequently lowering the rate‐limiting activation energy from 0.82 to as low as 0.15 eV. The feasibility is also proved by oxygen‐deficient Ni‐Co‐O nanosheets. This work not only establishes a clear atomic‐level correlation between cation substitution, anion vacancies, and OER performance, but also provides valuable insights for the rational design of highly efficient catalysts for OER.