Coupling of Bifunctional CoMn‐Layered Double Hydroxide@Graphitic C3N4 Nanohybrids towards Efficient Photoelectrochemical Overall Water Splitting

• Published in: Chemistry, an Asian journal Vol. 13; no. 8; pp. 1045 - 1052
• Main Authors: Arif, Muhammad, Yasin, Ghulam, Shakeel, Muhammad, Fang, Xiaoyu, Gao, Rui, Ji, Shengfu, Yan, Dongpeng
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 16-04-2018
• Subjects: Carbon nitride; Catalysis; Catalysts; Chemical synthesis; Chemistry; Current density; Electrolysis; Energy requirements; graphitic carbon nitride; hydrogen evolution reaction; Hydrogen evolution reactions; Hydroxides; layered compounds; Light irradiation; Nanostructure; Oxidation; oxygen evolution reaction; Photoelectric effect; Photoelectric emission; Water splitting
• ISSN: 1861-4728; 1861-471X
• DOI: 10.1002/asia.201800016

The development of durable, low‐cost, and efficient photo‐/electrolysis for the oxygen and hydrogen evolution reactions (OER and HER) is important to fulfill increasing energy requirements. Herein, highly efficient and active photo‐/electrochemical catalysts, that is, CoMn‐LDH@g‐C3N4 hybrids, have been synthesized successfully through a facile in situ co‐precipitation method at room temperature. The CoMn‐LDH@g‐C3N4 composite exhibits an obvious OER electrocatalytic performance with a current density of 40 mA cm−2 at an overpotential of 350 mV for water oxidation, which is 2.5 times higher than pure CoMn‐LDH nanosheets. For HER, CoMn‐LDH@g‐C3N4 (η50=−448 mV) requires a potential close to Pt/C (η50=−416 mV) to reach a current density of 50 mA cm2. Furthermore, under visible‐light irradiation, the photocurrent density of the CoMn‐LDH@g‐C3N4 composite is 0.227 mA cm−2, which is 2.1 and 3.8 time higher than pristine CoMn‐LDH (0.108 mA cm−2) and g‐C3N4 (0.061 mA cm−2), respectively. The CoMn‐LDH@g‐C3N4 composite delivers a current density of 10 mA cm−2 at 1.56 V and 100 mA cm−2 at 1.82 V for the overall water‐splitting reaction. Therefore, this work establishes the first example of pure CoMn‐LDH and CoMn‐LDH@g‐C3N4 hybrids as electrochemical and photoelectrochemical water‐splitting systems for both OER and HER, which may open a pathway to develop and explore other LDH and g‐C3N4 nanosheets as efficient catalysts for renewable energy applications.
Do the splits! Bifunctional electrocatalysts and photoelectrocatalysts for water‐splitting applications have been prepared by coupling CoMn‐layered double hydroxide (LDH) and graphitic C3N4 (g‐C3N4) through a facile in situ co‐precipitation method at room temperature (see figure). This is the first example of pure CoMn‐LDH and CoMn‐LDH@g‐C3N4 hybrids in electrochemical and photoelectrochemical water splitting for both oxygen and hydrogen evolution reactions.