Electrocatalytic water oxidation is a rate-determining step in the water splitting process; however, its efficiency is significantly hampered by the limitations of cost-effective electrocatalysts. Here, an advanced Co(OH)2 electrocatalyst with ultralow iridium (Ir) doping is developed to enable outstanding oxygen evolution reaction (OER) properties; that is, in a 1 M KOH medium, an overpotential of only 262 mV is required to achieve a current density of 10 mA cm-2, and a small Tafel slope of 66.9 mV dec-1 is achieved, which is markedly superior to that of the commercial IrO2 catalyst (301 mV@10 mA cm-2; 66.9 mV dec-1). Through the combination of experimental data and a mechanism study, it is disclosed that the high intrinsic OER activity results from the synergistic electron coupling of oxidized Ir and Co(OH)2, which significantly moderate the adsorption energy of the intermediates. Moreover, we have also synthesized Ru-Co(OH)2 nanosheets and demonstrated the universal syntheses of Ir-doped CoM (M = Ni, Fe, Mn, and Zn) layered double hydroxides (LDHs).

Boosting oxygen evolution of layered double hydroxide through electronic coupling with ultralow noble metal doping.

The application of renewable energy conversion devices is considered as one of the effective ways to alleviate the energy shortage and environmental pollution. Designing electrocatalysts with excellent performance and affordable price is promising to accelerate the reaction process and large‐scale application. At present, ruthenium (Ru)‐based nanomaterials have shown similar catalytic activity but superior price demand compared to commercial Pt/C. This undoubtedly makes Ru‐based nanomaterials a perfect candidate to replace advanced Pt catalysts. Significant progress is made in the rational design of Ru‐based electrocatalysts, but an in‐depth understanding of the engineering strategies and induced effects is still at an early stage. This review summarizes the modification strategies for enhancing the catalytic activity of Ru, including surface structure, metal element, nonmetal element, size, bimetallic oxides, and heterostructure engineering strategies. Then the induced electronic modulation effects generated by the intramolecular and intermolecular of the Ru‐based nanomaterials are elucidated. Further, the application progress of engineered Ru‐based nanomaterials for hydrogen and oxygen conversion reactions is highlighted, and the correlations of engineering strategies, catalytic activity, and reaction pathways are elaborated. Finally, challenges and prospects are presented for the future development and practical application of Ru‐based nanomaterials.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/aenm.202202119

Recent Advances in Engineered Ru‐Based Electrocatalysts for the Hydrogen/Oxygen Conversion Reactions

Ligand-free Synthesis of Noble Metal Nanocatalysts for Electrocatalysis

Oxygen and hydrogen generated by water electrolysis may be utilized as a clean chemical fuel with high gravimetric energy density and energy conversion efficiency. The hydrogen fuel will be the alternative to traditional fossil fuels in the future, which are near to exhaustion and cause pollution. In the present study, flowery-shaped In2MnSe4 nanoelectrocatalyst is fabricated by anion exchange reaction directly grown on nickel foam (NF) in 1.0 M KOH medium for oxygen evolution reaction (OER). The physiochemical and electrical characterization techniques are used to investigate the chemical structure, morphology, and electrical properties of the In2MnSe4 material. The electrochemical result indicates that synthesized material exhibits a smaller value of Tafel slope (86 mV/dec), lower overpotential (259 mV), and high stability for 37 h with small deterioration in the current density for a long time. Hence, the fabricated material responds with an extraordinary performance for the OER process and for many other applications in the future.

/pdf/flowery-ln2mnse4-novel-electrocatalyst-developed-via-anion-3nwszw1f.pdf

Flowery ln2MnSe4 Novel Electrocatalyst Developed via Anion Exchange Strategy for Efficient Water Splitting

Water splitting performance of metal and non-metal-doped transition metal oxide electrocatalysts

In response to the shortage of fossil fuels, efficient electrochemical energy conversion devices are attracting increasing attention, while the limited electrochemical performance and high cost of noble metal-based electrode materials remain a daunting challenge. The electrocatalytic performance of electrode materials is closely bound with their intrinsic electronic/ionic states and crystal structures. Apart from the nanoscale design and conductive composite strategies, heteroatom doping, particularly for nonmetal doping (e.g., hydrogen, boron, sulfur, selenium, phosphorus, and tellurium), is also another effective strategy to greatly promote the intrinsic activity of the electrode materials by tuning their atomic structures. From the perspective of electrocatalytic reactions, the effective atomic structure regulation could induce additional active sites, create rich defects, and optimize the adsorption capability, thereby contributing to the promotion of the electrocatalytic performance of noble metal-based electrocatalysts. Encouraged by the great progress achieved in this field, we have reviewed recent advancements in nonmetal doping for electrocatalytic energy conversion. Specifically, the doping effect on the atomic structure and intrinsic electronic/ionic state is also systematically illustrated and the relationship with the electrocatalytic performance is also investigated. It is believed that this review will provide guidance for the development of more efficient electrocatalysts.

Xinhua Lu

Papers

Nonmetal-doping of noble metal-based catalysts for electrocatalysis.