Developing highly efficient and affordable noblemetal-free catalysts toward the hydrogen evolution reaction (HER) is an important step toward the economical production of hydrogen. As a nonprecious-metal catalyst for the HER, molybdenum nitride (MoN) has excellent corrosion resistance and high electrical conductivity, but its catalytic activity is still inadequate. Here we report our findings in dramatically enhancing the HER activity of MoN by creating porous MoN@nitrogendoped carbon (MoN-NC) nano-octahedrons derived from metal−organic frameworks (MOFs). The composite catalyst displays remarkably high catalytic activity, demonstrating a low overpotential of 62 mV at a current density of 10 mA cm −2 (η 10 ), a small Tafel slope of 54 mV dec −1 , and a large exchange current density of 0.778 mA cm −2 while maintaining good stability. The enhancement in catalytic properties is attributed to the unique nanostructure of the MoN, the high porosity of the electrode, and the synergistic effect between the MoN and the nitrogendoped carbon substrate. The performances are among the best ever reported for nonprecious-metal-based electrocatalysts (comparable to those of a 20% Pt/C commercial catalyst), making the porous MoN-NC nano-octahedrons some of the most active and acid-stable electrocatalysts for the HER.

Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

A solid oxide fuel cell (SOFC) is a highly efficient device for converting chemical energy to electrical energy. In addition to the efforts to reduce the operating temperature of SOFCs to below 600 °C, research studies of the basic mechanism of CO2 poisoning on cathode materials are envisioned to improve the operation of dual-chamber SOFCs using ambient air. In this work, we comparatively studied the CO2 poisoning effect on two highly active perovskites SrSc(0.175)Nb(0.025)Co(0.8)O(3-δ) (SSNC) and Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) (BSCF), using complementary characterization techniques, e.g., powder X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), CO2-temperature-programmed desorption (CO2-TPD), and electrochemical impedance spectroscopy (EIS). The SSNC cathode shows better tolerance to CO2 as compared with BSCF, which is attributed to the absence of Ba, higher average metal-oxygen bond energy (ABE) of SSNC, and the higher acidity of Nb(5+) cations, whereas the oxygen vacancy concentration plays a less important role.

A novel strategy to tweak the oxygen evolution activity of nanofilms by exploiting the film-substrate redox interaction.

Practical application of hydrogen production from water splitting relies strongly on the development of low‐cost and high‐performance electrocatalysts for hydrogen evolution reaction (HER). The previous researches mainly focused on transition metal nitrides as HER catalysts due to their electrical conductivity and corrosion stability under acidic electrolyte, while tungsten nitrides have reported poorer activity for HER. Here the activity of tungsten nitride is optimized through rational design of a tungsten nitride–carbon composite. More specifically, tungsten nitride (WNx) coupled with nitrogen‐rich porous graphene‐like carbon is prepared through a low‐cost ion‐exchange/molten‐salt strategy. Benefiting from the nanostructured WNx, the highly porous structure and rich nitrogen dopant (9.5 at%) of the carbon phase with high percentage of pyridinic‐N (54.3%), and more importantly, their synergistic effect, the composite catalyst displays remarkably high catalytic activity while maintaining good stability. This work highlights a powerful way to design more efficient metal–carbon composites catalysts for HER.

The vital role of ethylenediaminetetraacetic acid on the structure and the oxygen reduction reaction activity of the non‐precious‐metal‐based pyrolyzed catalyst is reported and elaborated. The resultant catalyst can overtake the performance of commercial Pt/C catalyst in an alkaline medium.

Simple disordered perovskite oxides have been intensively exploited as promising electrocatalysts for the oxygen evolution reaction (OER) towards their application in water splitting, reversible fuel cells, and rechargeable metal-air batteries. Here, the B-site cation-ordered double perovskites Ba Bi Sc Co O , with two types of cobalt local environments, are demonstrated to be superior electrocatalysts for OER in alkaline solution, demonstrating ultrahigh catalytic activity. In addition, no obvious performance degradation is observed for the Ba Bi Sc Co O sample after a continuous chronopotentiometry test. The critical role of the ordered [Co ] and [Sc , Bi , Co ] dual environments in improving OER activity is exhibited. These results indicate that B-site cation-ordered double perovskite oxides may represent a new class of promising electrocatalysts for the OER in sustainable energy storage and conversion systems.

An abundant, highly active, and durable oxygen evolution reaction (OER) electrocatalyst is an enabling component for a more sustainable energy future. We report, herein, a molybdenum and niobium codoped B-site-ordered double perovskite oxide with a compositional formula of BaCoMoNbO (BCMN) as an active and robust catalyst for OER in an alkaline electrolyte. BCMN displayed a low overpotential of 445 mA at a current density of 10 mA cm. BCMN also showed long-term stability in an alkaline medium. This work hints toward the possibility of combining a codoping approach with double perovskite structure formation to achieve significant enhancement in the OER performance.