Sub-5 nm Ultra-Fine FeP Nanodots as Efficient Co-Catalysts Modified Porous g-C₃N₄ for Precious-Metal-Free Photocatalytic Hydrogen Evolution under Visible Light

Abstract

Sub-5 nm ultra-fine iron phosphide (FeP) nano-dots-modified porous graphitic carbon nitride (g-C3N4) heterojunction nanostructures are successfully prepared through the gas-phase phosphorization of Fe3O4/g-C3N4 nanocomposites. The incorporation of zero-dimensional (0D) ultra-small FeP nanodots co-catalysts not only effectively facilitate charge separation but also serve as reaction active sites for hydrogen (H2) evolution. Herein, the strongly coupled FeP/g-C3N4 hybrid systems are employed as precious-metal-free photocatalysts for H2 production under visible-light irradiation. The optimized FeP/g-C3N4 sample displays a maximum H2 evolution rate of 177.9 μmol h–1 g–1 with the apparent quantum yield of 1.57% at 420 nm. Furthermore, the mechanism of photocatalytic H2 evolution using 0D/2D FeP/g-C3N4 heterojunction interfaces is systematically corroborated by steady-state photoluminescence (PL), time-resolved PL spectroscopy, and photoelectrochemical results. Additionally, an increased donor density in FeP/g-C3N4 is evidenced from the Mott–Schottky analysis in comparison with that of parent g-C3N4, signifying the enhancement of electrical conductivity and charge transport owing to the emerging role of FeP. The density functional theory calculations reveal that the FeP/g-C3N4 hybrids could act as a promising catalyst for the H2 evolution reaction. Overall, this work not only paves a new path in the engineering of monodispersed FeP-decorated g-C3N4 0D/2D robust nanoarchitectures but also elucidates potential insights for the utilization of noble-metal-free FeP nanodots as remarkable co-catalysts for superior photocatalytic H2 evolution.

Z‐Scheme Photocatalytic Systems for Carbon Dioxide Reduction: Where Are We Now?

“…However, it is challenging for a single semiconductor to possess the overall potential that straddles both the CO 2 reduction reaction and the oxidation half‐reaction; even if there is one, the light response range of the semiconductor will be significantly shrunk due to its wide band gap [14, 15] . Moreover, during the photocatalytic process, these semiconductors usually suffer from the rapid recombination of their photogenerated electron‐hole pairs, which conspicuously lowers the photoconversion efficiency and restricts their practical applications [16–18] . Therefore, it is of utmost importance to develop ingenious tactics to overcome these shortfalls for the promotion of photocatalytic performance [19] …”

Single‐Site, Single‐Metal‐Atom, Heterogeneous Electrocatalyst: Metal–Organic‐Framework Supported Molybdenum Sulfide for Redox Mediator‐Assisted Hydrogen Evolution Reaction

“…In this context, photo‐, electro‐, or photoelectrochemical reduction of water (or hydronium ions) to molecular hydrogen, i. e ., the hydrogen evolution reaction (HER), is ideal. Coupling HER to the corresponding oxidative reaction, namely molecular oxygen evolution, yields overall water splitting, and thus, molecular hydrogen formation in a carbon‐neutral manner.…”

Fabrication of 2D/0D Heterojunction Based on the Dual Controls of Micro/Nano‐Morphology and Structure Towards High‐Efficiency Photocatalytic H2 Production

“…Recently, transition metal phosphides as replacement of noble metals have been put much emphasis in the electrocatalytic H 2 production, including FeP, CoP, MoP, Ni 2 P, Cu 3 P and so on, [34][35][36][37] which can serve as more effective cocatalysts for photocatalytic H 2 production. [38,39] For instance, we construct the unique PÀ CoÀ N surface bonding states on the surface of 2D g-C 3 N 4 nanosheet by using CoP nanodots as cocatalysts, obviously accelerating the transfer and separation of charge carriers and acting as sufficient active sites to improve the photocatalytic H 2 production activity. [40] Recently, some researches reveal that Ni 12 P 5 presents the excellent electrocatalytic activity for H 2 production reaction, [41,42] which suggests it is likely to be a cocatalyst candidate of up-g-C 3 N 4 .…”