Electrochemical production of hydrogen peroxide (H₂O₂) via the two-electron (2e⁻) pathway of oxygen reduction reaction (ORR) supplies an auspicious alternative to the current industrial anthraquinone process. Nonetheless, it still lacks efficient electrocatalysts to achieve high ORR activity together with 2e⁻ selectivity simultaneously. Herein, a boron-doped defective nanocarbon (B-DC) electrocatalyst is synthesized by using fullerene frameworks as the precursor and boric oxide as the boron source. The obtained B-DC materials have a hierarchical porous structure, befitting boron dopants, and abundant topological pentagon defects, exhibiting a high ORR onset potential of 0.78 V and a dominated 2e⁻ selectivity (over 95%). Remarkably, when B-DC electrocatalyst is employed in a real device, it achieves a high H₂O₂ yield rate (247 mg·L⁻¹·h⁻¹), quantitative Faraday efficiency (~ 100%), and ultrafast organic pollutant degradation rate. The theoretical calculation reveals that the synergistic effect of topological pentagon defects and the incorporation of boron dopants promote the activation of the O₂ molecule and facilitates the desorption of oxygen intermediate. This finding will be very helpful for the comprehension of the synergistic effect of topological defects and heteroatom dopants for boosting the electrocatalytic performance of nanocarbon toward H₂O₂ production.

Hydrogen generation from water splitting is of great prospect for the sustainable energy conversion. However, it is still challenging to explore stable and high-performance electrocatalysts toward hydrogen evolution reaction (HER) from saline water such as seawater due to the chloride corrosion. Herein, we developed a self-supported heterogeneous bimetallic phosphide (Ni₂P-FeP) array electrode that possesses excellent HER performance in alkaline saline water with an overpotential of 89 mV at 10 mA·cm⁻² and long-term stability over 90 h at 200 mA·cm⁻². The analysis showed that the heterostructure between the interfaces of Ni₂P-FeP plays a pivotal role in promoting the activity of catalyst. Moreover, the bimetallic phosphide nanoarrays can be employed as a shield for chlorine-corrosion resistance in the saline water, ensuring the long-term durability of hydrogen generation. When employed for alkaline saline water electrolysis, a current density of 100 mA·cm⁻² is achieved at cell voltage of 1.68 V. This work presents an effective approach for the fabrication of high-performance electrode for HER in alkaline saline environments.

Two-electron oxygen reduction reaction (ORR) catalysts are essential for the electrosynthesis of hydrogen peroxide (H₂O₂). MXenes, a rising family of two-dimensional (2D) transition metal carbides, have been extensively studied for energy storage and (photo)electrocatalysis due to their rich chemical compositions and tunable electronic structures. In this work, three representative MXenes of Ti₃C₂T_x, V₂CT_x, and Nb₂CT_x were selected for H₂O₂ electrosynthesis and we found that MXenes are inherent two-electron ORR catalysts with high H₂O₂ selectivity. In addition, this work critically evaluates their electrocatalytic activity and stability. Interestingly, Nb₂CT_x catalyst maintains better electrocatalytic activity and higher stability for a long time test, although the stability of Ti₃C₂T_x and V₂CT_x catalysts is poor owing to the metal dissolution property of Ti and V in alkaline media. Moreover, the assembled device based on Nb₂CT_x catalyst presents a high H₂O₂ production and a rapid organic dye decoloration ability.