Fabrication of a multijunction nitride-based Ti1.33N@BiVO4/GdIn2Se3 MXene heterostructure with enhanced optoelectronic and photoelectrochemical properties

• Rational design of an S-scheme heterojunction integrated with an in-plane double transition metal-based (i-DTM) MXene. • The successful fabrication of a nitride-based i-DTM MXene using a top-down strategy. • Comprehensive experimental investigation revealing the enhanced optoelectronic and photoelectrochemical properties of the material. A dual interfacial heterojunction of 2D-2D Ti 1.33 N@BiVO 4 /GdIn 2 Se 3 photocatalyst with enhanced photocatalytic properties was prepared. Microscopic images showed a 2D GdIn 2 Se 3 sheet sandwiching a decahedron and a tetragonal bipyramidal (010) exposed facet of BiVO 4 , 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 1.33 N@BiVO 4 /GdIn 2 Se 3 photocatalyst with suppressed charge carrier recombination. The Ti 1.33 N@BiVO 4 /GdIn 2 Se 3 composite realised a Schottky junction and S-scheme dual charge transfer mechanism. A Schottky junction was realised at the BiVO 4 @Ti 1.33 Ninterface, and at the GdIn 2 Se 3 /BiVO 4 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 1.08×10 21 cm −3 were achieved in the Ti 1.33 N@BiVO 4 /GdIn 2 Se 3 composite.