In-situ CdS nanowires on g-C3N4 nanosheet heterojunction construction in 3D-Optofluidic microreactor for the photocatalytic green hydrogen production.

Herein, we reported a simple and cost-effective fabrication method to develop an effective corrugated serpentine OFMR (C-SOFMR) with advanced features, such as expansion/contraction and wavy microstructure. A laminar flow with no back mixing was observed in plain serpentine OFMR (P-SOFMR). While, stretching and folding of fluid along with back mixing was observed in C-SOFMR. Further, the CdS nanowires on g-C 3 N 4 nanosheet (CN/CdS) heterojunction was synthesized in situ both P-SOFMR and C-SOFMR and utilized the device for the photocatalytic green hydrogen generation. The CN/CdS heterojunction endowed with narrow band gap energy (2.01 eV). The longer CdS nanowires (∼110 nm) benefit the electronic interface with CN in the CN/CdS heterojunction and lead to the spatial separation (reduced recombination) of excitons along the CdS axial direction. The charges generated were utilized efficiently for the HER reaction in both P-SOFMR and C-SOFMR at higher flow rates attributing to the rapid micro-mixing and mass transfer. The CN/CdS heterojunction showed the highest photocatalytic activity (6.38 μmol h−1 in C-SOFMR and 6.16 μmol h−1 in P-SOFMR at 1.0 mL min−1) due to its good optronic properties. This study is a path forward for the utilization of advanced optofluidic devices to produce green hydrogen directly from solar energy. [Display omitted] • Fabrication of plain and corrugated serpentine optofluidic microreactors (SOFMRs). • Growth of CdS nanowires on g-C3N4 nanosheet (CN/CdS) heterojunction in situ SOFMRs. • Stretching and folding of fluid along with back mixing in corrugated-SOFMR. • SOFMRs possess enriched transport properties due to rapid mixing. • Excitons were effectively used in SOFMRs for enhanced green hydrogen production. [ABSTRACT FROM AUTHOR]