Atom Walls Confined Hyperdispersed Pt Nanocrystal Electrocatalysts for a Photovoltaic-Integrated Energy Storage System

Platinum-based catalysts are widely used in catalysis and energy storage; however, their reaction activity is often compromised by the formation of large agglomerates during nanoparticle growth. In this study, we constructed “TiOx atomic walls” (TOAWalls) on multiwalled carbon nanotubes using a rotating chamber atomic layer deposition system, a method scalable to the tens-of-grams level. These uniformly dispersed TOAWalls effectively confine platinum nanoparticle growth, yielding highly dispersed platinum nanocrystals (∼2.4 nm) with an interparticle spacing of 1.8 nm, even at a tunable loading as low as 5.2 wt %. Concurrently, the TOAWalls induce electronic charge redistribution, thereby strengthening the coupling between the oxygen atoms and platinum metal sites. Attributed to the synergistic effect of atomic wall confinement and Pt–O coordination, this electrocatalyst exhibited stable performance over 100 h of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). When employed as a cathode in liquid zinc–air batteries, it yielded a power density of 277 mW cm–2 and sustained stable cycling performance for over 365 h, extending to 480 h in planar cell configurations. Capitalizing on the catalyst’s multifunctionality, we demonstrate an integrated photovoltaic–energy storage and hydrogen production system; this setup facilitates around-the-clock water-splitting by coupling flexible zinc–air batteries with photovoltaic power generation.