Designing highly active and more durable oxygen electrocatalysts for regenerative metal-air batteries and water splitting is of practical significance. Herein, an advanced Co/N–C-800 catalyst composed of abundant Co–N x structures and carbon defects derived from cobalt phthalocyanine is synthesized. Remarkably, this catalyst exhibits favorable catalytic performance toward the oxygen evolution reaction (OER) with a receivable overpotential of 274 mV in an alkaline medium achieving a current density of 10 mA cm–2 and a Tafel slope of 43.6 mV decade–1, outperforming the commercial RuO2 catalyst. It further displays a high half-wave potential (0.82 V) for the oxygen reduction reaction in 0.1 M KOH. Theoretical calculations reveal that the Co–N x active sites along with the carbon defects can decrease the adsorption energy of intermediates (OH*, O*, and OOH*) and enhance the electron-transfer ability, thus boosting the OER process.

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Developing powerful and tolerant catalysts toward hydrogen evolution reaction (HER) is fairly meaningful and critical for the conversion and utilization of green energy. In this work, we exploit an improved, reliable, and convenient strong electrostatic adsorption strategy to synthesize Ru‐based electrocatalysts containing ultra‐small Ru nanoparticles (NPs). As verified by experimental studies and characterization analysis, the optimized treatment can strengthen the powerful interaction for anchoring ultra‐small Ru NPs dispersed on carbon substrate and prevent the migration and agglomeration of Ru NPs during catalytic reactions. It is demonstrated that the designed Ru−KB−H−6H exhibits exceptional HER performance with low overpotential (η10) and Tafel slope (52 mV and 41.5 mV dec−1 in 0.5 M H2SO4, 53 mV and 61.0 mV dec−1 in 1.0 M KOH). As expected, Ru−KB−H−6H displays dramatical stability with no unacceptable decline of LSV performance after 8000 cycles and long‐term test. This finding paves a practical way to fabricate high‐efficient, and steady electrocatalysts toward HER for industrial applications.

Sustainable production of green energy is the most promising way to solve the present energy crisis. [1] Hydrogen is considered an ideal selection because of its high-energy density and zero emission of CO 2 , whose realization would be a revolutionary victory in the energy field. [2] Among the known technologies of hydrogen evolution, electrochemical water splitting operated through renewable energy is an efficient and mild pathway to collect purified hydrogen. [3] Water splitting proceeds via two half-reactions, including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Compared to the two-electron transfer process of HER, OER originating at the anode displays the kinetically sluggish involving four proton-coupled electron transfers to generate oxygen. [4] As reported, OER requires the electrode voltage of 1.23 V under standard conditions, which determines the baseline value for overall water splitting. [5] However, many additional factors, including the impedances of electrode materials and interface, electrolyte, and temperature that slow down the reaction rate, drive up the demand for action potential under a practical environment. [6] Particularly, the complexity of electrolyte composition with different pH levels raises higher requirements for catalysts, making electrode materials with strong corrosion resistance more valuable. [7] However, the achievements, describing catalysts with satisfactory performance toward HER and OER in the full pH range, are limited. [8] Therefore, the development of economical, efficient, and bifunctional electrocatalysts working in pH-universal electrolytes is an attractive and challenging task.To date, noble metal-based catalysts are recognized as the state-of-the-art catalysts for HER (Pt-based materials) and OER (Ir-based oxides-IrO 2 ). [9] Pt-based electrocatalyst effortlessly exhibits the objective rate of hydrogen production in acidic environments, as well as IrO 2 as the benchmark electrocatalyst efficaciously promotes the sluggish OER in the alkaline medium. However, the noble and scarce nature largely hinders the large-scale application of Pt/Ir. [10] Most importantly, their single function makes themselves impossible to accomplish overall water splitting alone. To continue this interesting research, researchers have made great efforts to explore suitable substitutes. The diverse materials containing non-precious metals and related composites have been explored and evaluated, due to their earth abundance, low cost, and high efficiency. [11] Despite these materials displaying inspiring activity being comparable to noble metals, they are limited to a narrow pH range, thus be difficult to steadily provide long-lasting active output. [12] Ruthenium (Ru), one of the cheaper Pt group metals, exhibits Pt-like HER activity due to the similar hydrogen bond strength with Pt. [13] Ru-based materials bring an eclectic