Fabrication of a multijunction nitride-based Ti_1.33N@BiVO₄/GdIn₂Se₃ MXene heterostructure with enhanced optoelectronic and photoelectrochemical properties

A dual interfacial heterojunction of 2D-2D Ti_1.33N@BiVO₄/GdIn₂Se₃ photocatalyst with enhanced photocatalytic properties was prepared. Microscopic images showed a 2D GdIn₂Se₃ sheet sandwiching a decahedron and a tetragonal bipyramidal (010) exposed facet of BiVO₄, covered by 2D Ti_1.33 N MXene nanosheets. The XRD data and HR-TEM analysis confirmed the successful fabrication of a multijunctional heterostructure. The optical studies showed a visible-light (460 to 550 nm) active Ti_1.33N@BiVO₄/GdIn₂Se₃ photocatalyst with suppressed charge carrier recombination. The Ti_1.33N@BiVO₄/GdIn₂Se₃ composite realised a Schottky junction and S-scheme dual charge transfer mechanism. A Schottky junction was realised at the BiVO₄@Ti_1.33Ninterface, and at the GdIn₂Se₃/BiVO₄ interface, an S-scheme pathway is observed. In agreement with the multijunction formation, the photoelectrochemical studies (EIS, OCVD, and PCR) showed an improvement in the charge carrier properties of the ternary composite. A low charge transfer resistance of 323Ω and a high charge carrier density of 1.08×10²¹ cm⁻³ were achieved in the Ti_1.33N@BiVO₄/GdIn₂Se₃ composite.