A fine 3d transition metal regulation strategy toward high-entropy alloy mesoporous nanotubes as efficient electrocatalysts

Abstract

High-entropy alloys (HEAs) are attracting considerable attention because of their interesting catalytic features, intrinsic thermodynamic stability and diversity of components. Nevertheless, the precise shaping low-dimensional architectures and fine-regulated catalytic performance are still challenging for HEAs. Herein, we propose a cost-effective general template-triggered method to prepare a class of quinary to septenary HEA mesoporous nanotubes (HEA mNTs). In particular, we explore the electron structure–activity relationship toward HEA mNTs with different 3d transition metal regulation by experiments and DFT calculations. As a proof of demonstration, Fe-regulated senary HEA mNTs (PtPdRuIrFeCu mNTs) with ∼1.5 nm wall experimentally unveil the excellent mass activity of 1.94 A/mgPt (1.22 A/mgnoble metals) @ 0.9 VRHE for ORR, which is 7.46- (5.30-) fold higher than commercial Pt/C in 0.1 M KOH. Density functional theory results further reveal that the differential oxygen adsorption energy (EO) of PtPdRuIrFeCu is closest to the theoretical optimal EO, corresponding to excellent ORR activity. Additionally, the linear relationship between the differential EO of HEA and the d band center of pure metals can provide a rapid screening method for HEA catalysts. HEA mNTs reported in this work are a class of prospective catalysts for the fuel cells and water splitting devices, and the would-be applications in sensors and energy storages look bright because of their charming characteristics.