First Author: Bolin Hu
Corresponding Author: Jianjun Zhang
DOI: 10.1016/j.cej.2026.176644
By combining experimental investigation with theoretical calculations, this study constructs a self-powered solar–wind hybrid hydrogen-production system integrating an S-scheme CdS/Cu₇S₄ heterojunction, a rotary-disc soft-contact triboelectric nanogenerator, and an adaptive power-management module. The work reveals how a pulsed bias further strengthens the built-in electric field and accelerates interfacial charge separation and redox kinetics. The integrated system achieves a hydrogen-evolution rate of 935.1 μL min⁻¹ m⁻²—34.5 times that of conventional photocatalysis.
In April 2026, Chemical Engineering Journal published online the latest work from Professor Jianjun Zhang’s team at Guizhou University on self-powered photoelectrocatalytic hydrogen production. The researchers integrated an S-scheme CdS/Cu₇S₄ heterojunction with a rotary-disc soft-contact triboelectric nanogenerator and an adaptive power-management module. The pulsed bias supplied by the triboelectric nanogenerator further strengthens the interfacial built-in electric field, accelerating photogenerated charge separation and interfacial redox kinetics.
Hydrogen is regarded as an ideal clean-energy carrier because of its high energy density, zero carbon emissions at the point of use, and renewable production potential. CdS has a narrow band gap of 2.4 eV and responds well to visible light, but pristine CdS suffers from photocorrosion and rapid recombination of photogenerated carriers. Coupling CdS with Cu₇S₄ to form an S-scheme heterojunction establishes an interfacial built-in electric field and promotes charge separation, although further improvement remains desirable.
Conventional external-bias power supplies consume energy and offer limited flexibility. In this study, a triboelectric nanogenerator harvests wind energy and provides a self-powered external bias to the S-scheme CdS/Cu₇S₄ heterojunction, creating a solar–wind hybrid hydrogen-production system and a new route for the synergistic utilization of renewable energy.
The study used an earlier-generation Perfectlight trace-gas reaction evaluation system. Its current-generation successor, the μGAS1001 Trace Gas Reaction Evaluation System, is suitable for catalytic reactions that generate trace amounts of gas, including photocatalytic overall water splitting and photocatalytic CO₂ reduction. The system integrates control, gas circulation, automated sampling and injection, and reactor modules.
XRD, XPS, HRTEM, SEM, and elemental mapping confirm the successful synthesis of the S-scheme CdS/Cu₇S₄ heterojunction. HRTEM reveals clear lattice fringes assigned to CdS (100) and Cu₇S₄ (0 16 0). Elemental maps show homogeneous integration of both components and intimate interfacial contact.
The rotary-disc soft-contact triboelectric nanogenerator produces alternating current through contact electrification and electrostatic induction. Optimizing torque, rotational speed, and the number of parallel units yields a maximum short-circuit current of 76.2 μA and a transferred charge of 446.6 nC. After regulation by the power-management module, charging efficiency increases by a factor of 2.7.
CdS/Cu₇S₄ exhibits a substantially higher photocurrent density and electrical conductivity than pristine CdS, together with a lower charge-transfer resistance. DFT calculations show electron transfer from Cu₇S₄ to CdS through the Cu–S pathway, forming an interfacial built-in electric field. Density-of-states and work-function analyses further demonstrate enhanced electrical conductivity in the composite.
Driven by the work-function difference, electrons migrate from Cu₇S₄ to CdS and establish an interfacial built-in electric field. In situ XPS shows that illumination decreases the electron density of CdS while increasing that of Cu₇S₄, supporting an S-scheme charge-transfer pathway. The surface potential and charge density increase by factors of 1.3 and 1.8, respectively, while the built-in electric-field strength rises by a factor of 1.5.
The system integrates the RS-TENG, a power-management module, and a photoelectrochemical cell. At a wind speed of 15 m s⁻¹, it supplies a stable 1 V bias to the CdS/Cu₇S₄ catalyst. Gas-chromatography measurements show a hydrogen-evolution rate of 935.1 μL min⁻¹ m⁻²—34.5 times higher than that obtained by photocatalysis alone—with an energy-conversion efficiency of 2.77%.
This study develops an RS-TENG-based, self-powered, dual-source hydrogen-evolution system using an S-scheme CdS/Cu₇S₄ heterojunction as the photocathode, thereby enabling the synergistic utilization of solar and wind energy. The interfacial built-in electric field and the external pulsed bias cooperatively suppress carrier recombination and accelerate electron transfer. The strategy may also be extended to photocatalytic CO₂ reduction, nitrogen reduction to ammonia, organic-pollutant degradation, and seawater-resource utilization.
Jianjun Zhang is an associate professor and master’s supervisor at the School of Chemistry and Chemical Engineering, Guizhou University. His research focuses on triboelectric nanogenerators, photoelectrocatalytic hydrogen evolution, and photoelectrocatalytic CO₂ reduction.
Bolin Hu, Mingkun Wu, Xiaoxia Lv, Jun Wang, Jianjun Zhang, Mengkui Tian, and Baodong Chen. “Interfacial Electric Fields from Triboelectric–Photocatalytic Coupling Drive Efficient Hydrogen Evolution.” Chemical Engineering Journal, 2026, 538: 176644.
