Abstract In our efforts to obtain electrocatalysts with improved activity for water splitting, meticulous design and synthesis of the active sites of the electrocatalysts and deciphering how exactly they catalyze the reaction are vitally necessary. Herein, we report a one‐step facile synthesis of a novel precious‐metal‐free hydrogen‐evolution nanoelectrocatalyst, dubbed Mo 2 C@NC that is composed of ultrasmall molybdenum carbide (Mo 2 C) nanoparticles embedded within nitrogen‐rich carbon (NC) nanolayers. The Mo 2 C@NC hybrid nanoelectrocatalyst shows remarkable catalytic activity, has great durability, and gives about 100 % Faradaic yield toward the hydrogen‐evolution reaction (HER) over a wide pH range (pH 0–14). Theoretical calculations show that the Mo 2 C and N dopants in the material synergistically co‐activate adjacent C atoms on the carbon nanolayers, creating superactive nonmetallic catalytic sites for HER that are more active than those in the constituents.
With the goal of constructing a carbon-free energy cycle, proton-exchange membrane (PEM) water electrolysis is a promising technology that can be integrated effectively with renewable energy resources to produce high-purity hydrogen. IrO2, as a commercial electrocatalyst for the anode side of a PEM water electrolyzer, can both overcome the high corrosion conditions and exhibit efficient catalytic performance. However, the high consumption of Ir species cannot meet the sustainable development and economic requirements of this technology. Accordingly, it is necessary to understand the OER catalytic mechanisms for Ir species, further designing new types of low-iridium catalysts with high activity and stability to replace IrO2. In this review, we first summarize the related catalytic mechanisms of the acidic oxygen evolution reaction (OER), and then provide general methods for measuring the catalytic performance of materials. Second, we present the structural evolution results of crystalline IrO2 and amorphous IrOx using in situ characterization techniques under catalytic conditions to understand the common catalytic characteristics of the materials and the possible factors affecting the structural evolution characteristics. Furthermore, we focus on three types of common low-iridium catalysts, including heteroatom-doped IrO2 (IrOx)-based catalysts, perovskite-type iridium-based catalysts, and pyrochlore-type iridium-based catalysts, and try to correlate the structural features with the intrinsic catalytic performance of materials. Finally, at the end of the review, we present the unresolved problems and challenges in this field in an attempt to develop effective strategies to further balance the catalytic activity and stability of materials under acidic OER catalytic conditions.
Wurtzite ZnO microspheres composed of radially aligned porous nanorods are prepared via a simple thermal treatment of a "pre-synthesized" zinc monoglycerolate precursor. The as-prepared hierarchical nanomaterial can serve as a highly sensitive sensing material for ethanol detection.
Wasserstoffentwicklung. In ihrer Zuschrift auf S. 10902 ff. beschreiben T. Asefa, W. Chen, X. Zou et al. einen effizienten Hybridkatalysator der Wasserstoffentwicklung. Ein synergistischer Effekt zwischen Molybdäncarbid-Nanopartikeln und N-Atomen aktiviert benachbarte C-Atome in stickstoffreichen Kohlenstoffnanoschichten.
Developing low-cost, environmentally friendly and efficient non-precious metal electrocatalysts as alternatives to noble metals for the hydrogen evolution reaction (HER) is highly essential for the sustainable advancement of green hydrogen energy. Herein, a novel heterostructured Ni3P/Ni nanoparticle anchored in nitrogen-doped mesoporous carbon nanofibers (Ni3P/Ni@N-CNFs) is prepared by a facile solid-phase calcination protocol. The results demonstrated that benefiting from the intensive electronic coupling effect at the interface of the Ni3P/Ni heterostructure, the electron configuration of the Ni active site is optimized and thus the favorable HER activity. Furthermore, the N-doped carbon nanofiber scaffold with an extensive mesoporous structure endows Ni3P/Ni@N-CNFs with abundant electrochemically active sites together with excellent conductivity and stability, contributing to fast electron/mass transport. As expected, the resultant Ni3P/Ni@N-CNF electrocatalyst exhibited exceptional HER catalytic properties under universal pH conditions, driving a current density of 10 mA cm-2 at pretty low overpotentials of 121 mV, 145 mV and 187 mV in acidic, basic and neutral solutions, respectively, and retaining the catalytic stability for over 60 h. This intriguing work represents a fresh perspective for designing and exploiting highly advanced phosphide electrocatalysts for green hydrogen fuel production.
Abstract Oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are key reactions in diverse energy conversion devices, highlighting the importance of efficient catalysts. Edge‐anchored single atom catalysts (E‐SACs) emerge as a special class of atomic structure, but the detailed configuration and its correlation with catalytic activity remain little explored. Herein, a total of 78 E‐SACs (E‐TM‐N x ‐C) have been constructed based on 26 transition metal (TM) species with three coordination patterns. Using structural stability and ORR/OER catalytic activity as the evaluation criteria, a few catalytic structures comparable to Pt (111) for ORR and IrO 2 (110) for OER are screened based on high‐throughput calculations. The screening results unveil that the E‐Rh‐N 4 ‐C configuration exhibits most efficient bifunctional activity for both ORR and OER with an overpotential of 0.38 and 0.61 V, respectively. Electronic structure analysis confirms the distinctive edge effects on the electronic properties of TM and N species, and the feature importance derived from machine learning illustrates the efficacy of E‐TM‐N x subunit configuration in determining the catalytic activity of E‐SACs. Finally, the trained Gradient Boosting Regression (GBR) model exhibits acceptable accuracy in predicting the OH intermediates adsorption strength for E‐SACs, thereby paving the way for expanding catalytic structures based on E‐SACs.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)