Heterointerface of all‐alkynyl‐protected Au <sub>28</sub> nanoclusters anchored on NiFe‐LDHs boosts oxygen evolution reaction: a case to unravel ligand effect
Quanli Shen, Longyun Shen, Leyi Chen, Lubing Qin, Yonggang Liu, Nicholas M. Bedford, Francesco Ciucci, Zhenghua Tang
Abstract
Abstract Ultrasmall Au nanoclusters have been proven to effectively enhance the catalytic performance of NiFe layered double hydroxides (NiFe‐LDHs) toward oxygen evolution reaction (OER), yet the surface ligand effect of the Au nanoclusters still remains elusive. Herein, a systematic study is reported to examine the OER performance of NiFe‐LDHs supported atom‐precise all alkynyl‐protected [Au 28 ( t BuC≡C) 17 ] − nanoclusters (Au 28 ‐Alkynyl in short) and thiolate‐protected Au 28 (TBBT) 20 (TBBT = 4‐tert‐butylbenzenethiol) counterparts (Au 28 ‐Thiolate in short). The Au 28 ‐Alkynyl cluster has characteristic absorbance feature, and its composition is verified by mass spectrometry. It possesses a drastically different structure from the reported mixed ligand protected Au 28 nanoclusters. Interestingly, the NiFe‐LDHs loaded with Au 28 ‐Alkynyl exhibited a superior OER performance than the sample loaded with Au 28 ‐Thiolate under the same conditions, evidenced by a smaller overpotential of 205 mV at the current density of 10 mA·cm −2 and a lower Tafel slope value of 41.0 mV·dec −1 in 1 mol·L −1 KOH. Such excellent performance is attributed to the interfaces created between the NiFe‐LDHs and the Au nanoclusters, as density functional theory calculations reveal that more significant charge transfer occurs in Au 28 ‐Alkynyl/NiFe‐LDHs catalyst, and more importantly, the energy barrier of the potential‐determining step in the OER process for Au 28 ‐Alkynyl/NiFe‐LDHs is much lower than that of Au 28 ‐Thiolate/NiFe‐LDHs hence favors the electrocatalytic reaction.