Enhancement of the Efficiency of g-C₃N₄ for Hydrogen Evolution by Bifunctionality of RuSe₂

Abstract

Adding a cocatalyst to a semiconductor catalyst is often considered an effective measure to increase the efficiency of the photocatalytic hydrogen evolution reaction. Nowadays, noble metals are the state-of-the-art cocatalysts for the hydrogen evolution reaction. Due to their high cost and scarcity, it is imperative to develop cocatalysts prepared from cheap and abundant elements. Here, RuSe2 was used as an effective substitute for precious metal promoters such as Pt to enhance the efficiency of g-C3N4 for the hydrogen evolution reaction. A high efficiency of 13417.3 μmol·g–1·h–1 was obtained. It was 214 times higher than that of g-C3N4 and 2.8 times higher than that of 3%Pt/g-C3N4. Density functional theory calculations were performed. The (210) and (200) crystal faces of RuSe2 showed lower ΔG H* than Pt(111), indicating higher hydrogen evolution efficiency. Compared with the Pt cocatalyst, metallic RuSe2 cocatalysts exhibited superior performance. Meanwhile, the electrocatalytic activity was also investigated in an alkaline medium. It showed a decent electrocatalytic activity and high stability. These findings might provide a prototype to develop cheap and efficient cocatalysts for large-scale water splitting.

RuSe2/CeO2 heterostructure as a novel electrocatalyst for highly efficient alkaline hydrogen evolution

“…The lattice spacing value of RuSe 2 is measured as 0.297 nm, which is associate with the (200) plane of RuSe 2 (figure S2(b)) [23]. Moreover, as shown in the HRTEM image of RuSe 2 /CeO 2 in figure 1(g), the lattice spacing value of 0.297 is associate with the (200) face of RuSe 2 , and the 0.312 nm interplanar distance points to the (111) face of CeO 2 , indicating the formation of the RuSe 2 /CeO 2 heterojunction [38,39]. The EDS spectrum (figure S3) and corresponding mapping results (figures 1(h)-(l)) of RuSe 2 /CeO 2 show the homogeneous presence of Ru, Se, Ce, and O elements.…”

Potassium-Derived Charge Channels in Boron-Doped g-C3N4 Nanosheets for Photocatalytic NO Oxidation and Hydrogen Evolution

“…Among them, the PL intensity of CN-BK was significantly lower than that of CN-B without K-derived charge channels, which indicated that the existence of K-derived charge channels played an important role in the separation of electrons and holes. In addition, the electrochemical impedance spectra (EIS) shown in Figure c exhibited that CN-BK had the smallest arc radius, which indicated that CN-BK possessed the smaller charge transfer resistance and can easily transfer electrons . PL and EIS spectra indicated that the contribution of single element doping to charge separation and transfer was limited.…”

Influence of Ion Exchange on Photoresponsive Properties of Potassium Poly(heptazine imide)

“…Therefore, CN polymers are expected to be the next-generation photocatalysts, with current research specifically investigating photocatalysts that function under visible-light irradiation. However, as several papers have recently reported, the high recombination rate of photogenerated excitons and the inadequate active surface area of the CN polymer limit the photoactivity of this material. − To date, substantial efforts have been devoted toward improving the photoactivity of the CN polymer by increasing its active surface area, decreasing its energy gap for enhanced photoabsorption via heteroatom doping, employing various kinds of metal compounds as co-catalysts, − and facilitating free-carrier generation at its interfaces using noble and transition metals. ,, Recently, metal poly­(heptazine imide) (MPHI), in which various metal ions (M + ), mainly alkali metal ions, are coordinated to the poly­(heptazine imide) (PHI) framework, has received considerable attention. MPHI is an ionic two-dimensional CN polymer with a robust heptazine ring composed of six carbons and seven nitrogen atoms as a building unit.…”