Accelerated bubble departure and reduced overpotential with nanoengineered porous bifunctional Ni5P4 electrocatalyst for PV-driven water splitting. (22nd October 2022)

• Record Type: Journal Article
• Authors: Lu, Xinnan; Lalwani, Shubra; Yuan, Lin; Abdelsalam, Mohamed Abbas; AlMarzooqi, Faisal; Zhang, TieJun
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 86(2022)
• Page Start: 36504
• Page End: 36516
• Publication Date: 2022-10-22
• Subjects: Bubble dynamics -- Hierarchical porous electrode -- Nickel phosphide -- Water splitting -- Solar-driven hydrogen production; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.08.189
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Solar-driven green hydrogen production is a promising sustainable technology though large-scale solar water splitting remains challenging due to expensive electrocatalyst. Herein, we propose a facile and low-cost approach to fabricate nanoengineered hierarchically porous Ni5 P4 electrocatalyst (p-Ni5 P4 ), which provides high surface area and enables fast gas diffusion. By coating p-Ni5 P4 on Ni foam (NF), p-Ni5 P4 @NF has pores ranging from 50-500 nm to 200–600 μm and enlarges the electrochemically-active surface area by 5 times. p-Ni5 P4 @NF offers abundant cavities for gas nucleation and fast growth of H2 bubble, and small bubbles (10–50 μm) depart quickly owing to the reduced contact line. By enhancing gas transfer and reducing bubble overpotential over 29%, p-Ni5 P4 @NF achieves excellent electrocatalytic performance with a low HER (145 mV), OER (197 mV) and overall water splitting potential (1.54 V) at 10 mA cm −2 . Powered by multijunction PV cell, the full electrolytic cell records a high solar-to-hydrogen efficiency of 14.5%. Graphical abstract: Image 1 Highlights: Hierarchically porous Ni5 P4 electrocatalyst is fabricated with a facile and low-cost approach. Bubble dynamics at electrode-electrolyte interface affect transport overpotential. Nanoscale pores of Ni5 P4 accelerate bubble departure and reduce bubble overpotential over 29%. p-Ni5 P4 @NF achieves excellent performance as HER/OER bifunctional electrocatalyst. PV-driven electrolytic cell achieves an outstanding solar-to-H2 efficiency of 14.5%.