Developing efficient non‐precious bifunctional electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is highly critical for overall water splitting. Herein, vertically aligned CoTe and NiTe nanoarrays are synthesized in situ grown on Ni foams (marked as CoTeNR/NF and NiTeNR/NF) via a facile hydrothermal method, and further explore their catalytic activities for overall water splitting. The CoTeNR/NF catalyst exhibits not only excellent OER performance with a low overpotential of 350 mV to deliver 100 mA cm−2, but also high HER activity only requiring 202 mV overpotential to yield 10 mA cm−2 in alkaline condition. Moreover, experimental technique and density functional theory are combined together to reveal that the real active sites of CoTeNR/NF for OER are from the in situ generated CoOOHspecies on CoTeNR/NF in the OER process, and also propose a new HER performance evaluation criteria of using H2O adsorption energy, H2O dissociation barrier, and H2/OH− desorption energy as an indicator. The new criteria can satisfactorily evaluate the HER performance of as‐synthesized samples, while the traditional one of using H adsorption energy as an indicator fails in the HER performance evaluation of as‐synthesized samples. It is expected that the new evaluation criteria can be used as a general criteria to evaluate the HER performance of other electrocatalysts.

No abstract

Pursuing highly active and stable bifunctional electrocatalysts for hydrogen / oxygen evolution reaction (HER/OER) is significantly important for overall water splitting. Herein, we prepare the ultra-small Ru nanoparticles embedded on...

No abstract

Developing highly efficient and earth‐abundant electrocatalysts for the oxygen evolution reaction (OER) is significantly important for water‐splitting. Here, for the first time it is reported that the physically adsorbed metal ions (PAMI) in porous materials can be served as highly efficient OER electrocatalysts, which provides a universal PAMI method to develop electrocatalysts. This PAMI method can be applied to almost all porous supports, including graphene, carbon nanotubes, C3N4, CaCO3, and porous organic polymers and all the systems exhibit excellent OER performance. In particular, the as‐synthesized Co0.7Fe0.3CB exhibits a small overpotential of 295 mV and 350 mV at the current density of 10 mA cm−2 and 100 mA cm−2, respectively, which exceeds commercial 40 wt% IrO2/CB and most reported non‐noble metal‐based OER catalysts. Moreover, the mass activity of Co0.7Fe0.3CB reaches 643.4 A g−1 at the overpotential of 320 mV, which is nearly 4.7 times higher than that of 40 wt% IrO2/CB. In addition, the advanced ex situ and in situ synchrotron X‐ray characterizations are carried out to unravel the PAMI synthetic process. In short, this PAMI method will break the conversional understanding, i.e., the most OER catalysts are synthesized chemically, because the new PAMI method does not require any chemical synthesis, which therefore opens a new avenue for the development of OER electrocatalysts.