Enhanced Photocatalytic Hydrogen Evolution of the Hydrogenated Deficient g‐C₃N₄ via Surface Hydrotreating

Abstract

Unreacted amino groups (−NHx) existed in the bulk g‐C3N4 always act as charge trap sites which resulting in low photocatalytic activity. In this paper, the hydrogenated deficient g‐C3N4 (HDCN) was prepared by calcining bulk g‐C3N4 with NaBH4 under an inert atmosphere. It was found that −NHx groups were absolutely reduced into both nitrogen vacancies and the cyano groups (−C≡N groups) in the frameworks of g‐C3N4 after this surface hydrotreating. Therefore, the photo‐induced carrier recombination is suppressed dues to the disappeared −NHx groups. As a result, the HDCN sample displayed a higher photocatalytic H2 evolution activity than the bulk g‐C3N4.

Vacancy-modified g-C3N4and its photocatalytic applications

“…The hydrogenated g-C 3 N 4 sample exhibited a narrower bandgap and red-shift absorption, arising from its N 2c vacancies and cyano groups, which worked as strong electron-withdrawing sites, thus promoting the efficient transfer and separation of photo-induced carriers and exhibiting higher photocatalytic H 2 evolution activity than the bare g-C 3 N 4 . 115…”

“…The hydrogenated g-C 3 N 4 sample exhibited a narrower bandgap and red-shift absorption, arising from its N 2c vacancies and cyano groups, which worked as strong electron-withdrawing sites, thus promoting the efficient transfer and separation of photo-induced carriers and exhibiting higher photocatalytic H 2 evolution activity than the bare g-C 3 N 4 . 115 Recently, N 2c vacancy-and cyano groups-co-modified atomically layered g-C 3 N 4 was prepared through a facile two-step thermal treatment. The atomically layered g-C 3 N 4 with N v and cyano groups provided more active sites and decreased the transferring distances of photogenerated charge carriers.…”

In Situ Photodeposition of Au Nanoparticle Plasma: Enhanced Defect-State g-C3N4 Photocatalytic Hydrogen Evolution

“…The relative intensities of the peaks corresponding to C–NH x of HCN are enhanced compared to those of CN. C–NHx and –CN having similar C 1s binding energies suggests the presence of –CN in the HCN sample . As shown in Figure b, three peaks at 398.6, 400.2, and 401.1 eV can be observed in the spectra of the three samples of N 1s, belonging to C–NC, N–(C) 3 , and C–NHx, respectively.…”

Photocatalytic Water Splitting for H2 Production via Two‐electron Pathway

“…Structure modulation is also an attractive strategy for photocatalyst engineering. Among variously available semiconductors, carbon nitride (g‐C 3 N 4 ) has attracted increasing attention because of its suitable band structure, excellent chemical stability, and low production cost [51] . The narrow band gap of g‐C 3 N 4 (2.7 eV) is sufficient for photocatalytic water splitting, attracting tremendous efforts to elevate the reaction efficiency [52] .…”