Role of MoS2/rGO co-catalyst to enhance the activity and stability of Cu2O as photocatalyst towards photoelectrochemical water splitting

A heterostructural MoS2QDs@UiO-66 nanocomposite for the highly efficient photocatalytic degradation of methylene blue under visible light and simulated sunlight

The development of recyclable photocatalysts with high activity and stability has piqued the interest of researchers in the field of wastewater treatment. In this study, an ultrasonic probe approach was used to immerse a sequence of heterojunctions formed by metal-organic frameworks (UiO-66) and different amounts of molybdenum disulfide quantum dots (MoS2QDs), resulting in a highly recyclable MoS2QDs@UiO-66 photocatalyst. Multiple advanced techniques, such as XPS, XRD, TEM, XRF, and UV-vis spectrophotometry, were used to characterize and confirm the successful preparation of UIO-66 impregnated with MoS2QDs. The results indicated that the best heterostructure catalyst exhibited superior efficiency in the photocatalytic degradation of methylene blue (MB) in water, achieving approximately 99% removal within 30 minutes under simulated sunlight, while approximately 97% removal under visible light. The outstanding photocatalytic performance is predominantly attributed to the photoinduced separation of carriers in this heterostructure system. This study proposes a unique, simple, and low-cost method for improving the degradation performance of organic contaminants in water.

Novel visible-light-active P-g-CN-based α-Bi2O3/WO3 ternary photocatalysts with a dual Z-scheme heterostructure for the efficient decomposition of refractory ultraviolet filters and environmental hormones: Benzophenones

The ubiquitous and refractory benzophenone (BP)-type ultraviolet filters, which are also endocrine disruptors, were commonly detected in the aquatic matrix and could not be efficiently removed by conventional wastewater treatment processes, thus causing extensive concern. Herein, a novel ternary nanocomposite, P-g-CN/α-Bi2O3/WO3 (P-gBW), was successfully fabricated by mixing cocalcinated components and applied to the decomposition of BP-type ultraviolet filters. The dual-Z-scheme heterostructure of P-gBW enhances visible-light absorption, efficiently facilitates separation and mobility, and prolongs the lifetime of photoinduced charge carriers via double charge transfer mechanisms. The optimum 95 wt% P-gBW exhibited excellent photocatalytic activity, degrading 96% 4-hydroxy benzophenone (4HBP) within 150 min and 93% 2,2',4,4'-tetrahydroxybenzophenone (BP-2) within 100 min under visible-light illumination, respectively. The pseudo-first-order rate constant of 4HBP (1.15 h-1) was 6.8-, 3.1-, 3.3- and 2.2-fold higher than those of WO3, P-g-CN, α-Bi2O3, and P-g-CN/α-Bi2O3, respectively, while that of BP-2 (1.71 h-1) was 5.2-, 2.2-, 3.2- and 1.5-fold higher, respectively. The improved photocatalytic degradation was attributed to efficient photoinduced charge carrier separation and migration and prevented the recombination of electron holes, as verified by photoluminescence, transient photocurrent response, and electrochemical impedance spectroscopy. Trapping experiments, electron paramagnetic resonance, and band energy position indicated an efficient dual-Z-scheme heterostructure.

Enhancing the activity and stability of Cu2O nanorods via coupling with a NaNbO3/SnS2 heterostructure for photoelectrochemical water-splitting

We synthesized a stable copper-based heterostructure catalyst, NaNbO3/SnS2/Cu2O for photoelectrochemical water-splitting applications with improved activity, stability, and inhibited photocorrosion in Cu2O.