Heterostructured NiTe/Ni2P nanoarrays as high-activity electrocatalysts for the oxygen evolution reaction in seawater splitting

Abstract

Scale-up hydrogen production from natural seawater presents a promising avenue to address the escalating depletion of fossil fuel resources. However, direct seawater splitting (DSS) remains a formidable challenge, primarily due to the deficiency of efficient, stable, and cost-effective catalysts for the oxygen evolution reaction (OER). In this paper, we demonstrate the fabrication of a self-supported heterostructured nanoarray electrocatalyst, namely, NiTe/Ni₂P, which exhibits exceptional performance and durability in the OER in alkaline seawater conditions. Remarkably, this innovative catalyst displays an overpotential of merely 312 mV to achieve a current density of 100 mA cm⁻². Moreover, the overall seawater splitting (OSS) process can be achieved at a cell voltage of 1.68 V while maintaining a high faradic efficiency (FE) of nearly 100 % for the OER, alongside exceptional stability exceeding 100 h of continuous testing. We have validated the presence of heterostructures and strong interactions between NiTe and Ni₂P, as well as the Cl^- repelling capability resulting from the incorporation of P, which induces a more negatively charged surface. These aforementioned factors are posited as the fundamental drivers behind the catalyst's extraordinary performance and steadfastness in the OER during DSS. Moreover, this strategic approach harbors tremendous potential for the systematic development of catalysts exhibiting exceptional OER performance within the realm of DSS.