Heterointerface of all-alkynyl-protected Au28 nanoclusters anchored on NiFe-LDHs boosts oxygen evolution reaction: a case to unravel ligand effect

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((BuC)-Bu-t equivalent to 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 center dot cm-2 and a lower Tafel slope value of 41.0 mV center dot dec(-1) in 1 mol center dot 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.

Automated summary

A systematic study is reported to examine the enhanced oxygen evolution reaction (OER) performance of NiFe layered double hydroxides (NiFe-LDHs) by loading atom-precise all alkynyl-protected [Au-28((BuC)-Bu-t equivalent to C)(17)](-) nanoclusters on their surface. The loaded Au nanoclusters exhibit a significantly lower overpotential and Tafel slope compared to thiolate-protected Au-28(TBBT)(20) nanoclusters, indicating improved electrocatalytic activity. This enhanced performance is attributed to the interfaces created between NiFe-LDHs and Au nanoclusters, leading to more significant charge transfer and a lower energy barrier for the potential-determining step in the OER process.