Rational Design and Fabrication of Noble‐metal‐free Ni_xP Cocatalyst Embedded 3D N‐TiO₂/g‐C₃N₄ Heterojunctions with Enhanced Photocatalytic Hydrogen Evolution

Abstract

Developing low‐cost and efficient noble‐metal‐free photocatalytic materials is crucial for the hydrogen production through water splitting. Herein, N‐TiO2/g‐C3N4 heterostructure loaded with a noble‐metal‐free NixP cocatalyst was prepared by the combination of ammonia etching and photo‐reduction deposition method. The results demonstrated that N‐doped TiO2 (N‐TiO2) nanosheets were formed and stood upright on the surfaces of g‐C3N4 nanosheets, forming a 3D structure. The ternary hybridization of N‐TiO2/g‐C3N4@NixP hierarchical nanostructure was a promising strategy to achieve highly efficient photocatalytic H2 evolution, showing an optimized hydrogen evolution rate of 5438 μmol g−1⋅h−1 using 300 W Xe lamp as irradiation source, which was 7.5 times higher than that of N‐TiO2/g‐C3N4. The enhanced photocatalytic activity was ascribed to the combined effects of NixP cocatalyst loading and the formation of the intimate nanoheterojunctions between TiO2 nanosheets and g‐C3N4 nanosheets, which were favorable for promoting charge transfer. The present work would provide a novel facile preparation and practical application of many other noble‐metal‐free metal phosphides as a highly efficient cocatalyst for hydrogen production through water splitting.

The Role of Surface Texture on the Photocatalytic H2 Production on TiO2

“…. ) [101,104,[116][117][118][119][120][121] have been recently reported as active materials to (i) delocalize the electron in the conduction band thanks to their proper work functions (significantly lower than the CB of the titania), (ii) decrease the overpotentials for the proton reduction. An overall agreement on the role of the carbonaceous phase during the photocatalytic process under irradiated hybrid systems has not been reached yet.…”

S‐Scheme Heterojunction TiO2/CdS Nanocomposite Nanofiber as H2‐Production Photocatalyst

“…At present, environmental deterioration and energy crisis are two primary problems that pose a serious threat on the survival of mankind . Clean hydrogen (H 2 ) production offers potential opportunity to handle the challenges because H 2 energy has the merits of high caloric power, no pollution, and inexhaustible supply from water . Semiconductor‐driven photocatalytic H 2 evolution from water splitting is one of the most sustainable method for H 2 production .…”

“…Recently, hybridizing TiO 2 with narrow band gap semiconductors, for example, BiVO 4 , g‐C 3 N 4 , and CdS, has proven to be an efficient strategy to promote the separation of photogenerated electron‐hole pairs and enhance visible light absorption. Among them, CdS is often used to assemble a type‐II heterojunction with TiO 2 because of its high visible light response and well‐matched energy band structure .…”

Truncated octahedral bipyramidal TiO2/MXene Ti3C2 hybrids with enhanced photocatalytic H2 production activity

“…[7][8][9][10] However, in practical applications, there are still many problems with TiO 2 due to the fast recombination of photogenerated carriers and low light utilization capacity. 11,12 Therefore, many strategies, such as modifying co-catalysts, [13][14][15][16][17][18][19] doping impurities, [20][21][22][23] and changing its shape, 24,25 have been proposed to address these issues. Among these strategies, co-catalysts have been successfully developed for enhancing the activity and stability of TiO 2 .…”