To meet the practical demand of overall water splitting and regenerative metal–air batteries, highly efficient, low‐cost, and durable electrocatalysts for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) are required to displace noble metal catalysts. In this work, a facile solid‐state synthesis strategy is developed to construct the interfacial engineering of W2N/WC heterostructures, in which abundant interfaces are formed. Under high temperature (800 °C), volatile CNx species from dicyanodiamide are trapped by WO3 nanorods, followed by simultaneous nitridation and carbonization, to form W2N/WC heterostructure catalysts. The resultant W2N/WC heterostructure catalysts exhibit an efficient and stable electrocatalytic performance toward the ORR, OER, and HER, including a half‐wave potential of 0.81 V (ORR) and a low overpotential at 10 mA cm−2 for the OER (320 mV) and HER (148.5 mV). Furthermore, a W2N/WC‐based Zn–air battery shows outstanding high power density (172 mW cm−2). Density functional theory and X‐ray absorption fine structure analysis computations reveal that W2N/WC interfaces synergistically facilitate transport and separation of charge, thus accelerating the electrochemical ORR, OER, and HER. This work paves a novel avenue for constructing efficient and low‐cost electrocatalysts for electrochemical energy devices.

Nanogenerators capable of harvesting energy from environmental mechanical energy are attractive for many applications. In this paper, we present a simple, low-cost approach to convert low-frequency mechanical energy into electric power using piezoelectric ZnO nanorods grown on a common paper substrate. This energy conversion device has ultrahigh flexibility and piezoelectric sensitivity and can produce an output voltage of up to 10 mV and an output current of about 10 nA. It is demonstrated that the device's electric output behavior can be optionally changed between four types of mode simply by controlling the straining rate. Furthermore, it is also shown that the electric output can be enhanced by scaling the size of the device. This energy-harvesting technology provides a simple and cost-effective platform to capture low-frequency mechanical energy, such as body movements, for practical applications.

Nonoxides have been widely employed as highly efficient catalysts for water splitting. However, these nonoxides suffer from obvious surface transformation and poor structural stability, which must be urgently remedied. Herein, the interfacial engineering of Co4N via mesoporous nitrogen-doped carbon (NC) was first carried out, in which NC can significantly suppress the oxidization of Co4N in alkaline media, ensuring the efficient interfacial charge transport between Co4N and NC. As a result, extremely low overpotentials @10 mA cm–2 of 62 mV (hydrogen evolution reaction, HER) and 257 mV (oxygen evolution reaction, OER) and small Tafel slopes of 37 mV (HER) and 58 mV dec–1 (OER) were achieved in alkaline media. Theoretical calculations suggest that their synergetic coupling effects can significantly facilitate the charge-transfer process and further greatly reduce the energy barrier for water splitting. This work underscores the importance of the surface engineering of nonoxides and efficient approaches for the design of stable catalysts for electrocatalysis.