MXene Schottky Functionalized Z-scheme Ternary Heterostructure for Enhanced Photocatalytic H₂O₂ Production and H₂ Evolution

Abstract

The design and development of a multiheterostructure interface signifies a promising route to overcome the drawbacks of single-component and traditional heterostructured photocatalysts. Herein, a one-dimensional (1D)/two-dimensional (2D)/2D heterostructure, α-MnO 2 @B/O-g-C 3 N 4 /d-Ti 3 C 2 , is constructed by a facile two-step synthesis method to ensure charge separation and is utilized for photocatalytic H 2 O 2 production and H 2 evolution. The formation of the individual materials and nanohybrids as well as the 1D/2D/2D interfacial interaction is ascertained by X-ray diffraction, Raman, and electron microscopy studies, respectively. 5-MX/MBOCN shows optimum photocatalytic H 2 O 2 production (2846.4 μmol h −1 g −1 ) with 10% ethanol and H 2 evolution (897.2 μmol h −1 ), which is, respectively, 2.5 and 1.6 times higher than that of the binary MBOCN counterpart. The greater cathodic current density from linear sweep voltammetry, hindered charge recombination from electrochemical impedance spectroscopy and photoluminescence measurement, and better photodurability all systematically demonstrated the improved photocatalytic performance. The mechanistic investigation shows that in the ternary hybrid, electrons flow from MnO 2 to boron-doped g-C 3 N 4 through a Z-scheme charge dynamics and then electrons flow to the d-MXene surface, which acts as a cocatalyst. The charge transfer dynamics is corroborated by time-resolved photoluminescence, cyclic voltametric analysis, trapping experiment, and ESR analysis. This work instigates the design and development of a high-efficiency cocatalystintegrated Z-scheme photocatalyst with strong interfacial interaction and high redox ability for solar to chemical energy conversion.

Recent advancements in graphitic carbon nitride based direct Z- and S-scheme heterostructures for photocatalytic H2O2 production

“…Similarly, Parida et al developed a Schottky functionalized direct Z-scheme ternary heterojunction photocatalyst, α-MnO 2 @B/O-g-C 3 N 4 /d-Ti 3 C 2 , employing a simple two-step synthesis method for photocatalytic H 2 O 2 production. 206 The 5-MX/MBOCN variant, with 10% ethanol, achieved an optimal photocatalytic H 2 O 2 formation rate of 2846.4 μmol h −1 g −1 , which was 2.5 times higher than its binary MBOCN counterpart. The enhanced performance is owing to the combination of direct Z-scheme charge migration and the incorporation of a metallic delaminated MXene cocatalyst in the Schottky junction, providing a novel approach for optimizing charge migration and boosting H 2 O 2 photosynthesis efficiency.…”

Construction of a 1D/2D S-Scheme Heterojunction of Mo-Doped WO3/In-Doped Carbon Nitride for Efficient Hydrogen Peroxide Photosynthesis

“…The industrial method of producing H 2 O 2 is the anthraquinone method, which involves complicated processes, high energy consumption, and environmental pollution. , In the context of the reduction of carbon dioxide emissions, the solar-driven production of H 2 O 2 based on semiconductor photocatalysis has been considered to be a promising strategy for producing H 2 O 2 . The photocatalytic conversion of H 2 O and O 2 to H 2 O 2 by the use of semiconductor photocatalysts is a green, low-cost, and safe method. − The production of H 2 O 2 via the photocatalytic process in the presence of H 2 O and O 2 involves two paths, i.e., the oxygen reduction reaction (ORR) and the water oxidation reaction (WOR). − The ORR can be classified into indirect two-step single-electron reduction (O 2 → • O 2 – → H 2 O 2 ) and direct one-step double-electron reduction (O 2 → H 2 O 2 ). Similarly, the WOR can be divided into indirect two-electron WOR (H 2 O → • OH → H 2 O 2 ) and direct two-electron WOR (H 2 O → H 2 O 2 ).…”

Can Doped-MXene-Based Supercapacitors Be the Game-Changer for Future Energy Landscape? A Critical Perspective

“…MXenes, a novel class of 2D materials comprising early transition metal carbides, nitrides, and carbonitrides, have arisen from the selective etching of A elements from MAX phase ceramic materials. − MXenes are denoted as M n +1 X n T x , where T signifies surface termination groups and x denotes the number of terminal groups per formula unit. The synthesis and post-treatment processes of MXenes allow for the manipulation of structural features such as interlayer spacing, pore structure, surface termination groups, heteroatom doping, defects, and vacancies, which greatly influence electrochemical properties such as electron/ion transport, redox active sites, kinetics, and activity without forming any composite. − Therefore, extensive research efforts have been dedicated to MXene-based electrode materials for SCs. Also, our research group has undertaken thorough investigations within the field of supercapacitors and MXene-based catalysts, thereby making significant scholarly contributions to the scientific arena. − …”

“…The synthesis and post-treatment processes of MXenes allow for the manipulation of structural features such as interlayer spacing, pore structure, surface termination groups, heteroatom doping, defects, and vacancies, which greatly influence electrochemical properties such as electron/ion transport, redox active sites, kinetics, and activity without forming any composite. − Therefore, extensive research efforts have been dedicated to MXene-based electrode materials for SCs. Also, our research group has undertaken thorough investigations within the field of supercapacitors and MXene-based catalysts, thereby making significant scholarly contributions to the scientific arena. − …”

“…MXenes have gathered attention among various electrode materials for their unique ability to provide both EDLC and pseudocapacitive behavior, depending upon the intrinsic structure and electrolytes. MXenes, a novel class of 2D materials comprising early transition metal carbides, nitrides, and carbonitrides, have arisen from the selective etching of A elements from MAX phase ceramic materials. − MXenes are denoted as M n +1 X n T x , where T signifies surface termination groups and x denotes the number of terminal groups per formula unit. The synthesis and post-treatment processes of MXenes allow for the manipulation of structural features such as interlayer spacing, pore structure, surface termination groups, heteroatom doping, defects, and vacancies, which greatly influence electrochemical properties such as electron/ion transport, redox active sites, kinetics, and activity without forming any composite. − Therefore, extensive research efforts have been dedicated to MXene-based electrode materials for SCs.…”