3D printed photoreactor with immobilized graphitic carbon nitride: A sustainable platform for solar water purification.

Solar-energy-enabled photocatalysis is promising for sustainable water purification. However, photoreactor design, especially immobilizing nano-sized photocatalysts, remains a major barrier preventing industrial-scale application of photocatalysis. In this study, we immobilized photocatalytic graphitic carbon nitride on chitosan to produce g-C3N4/chitosan hydrogel beads (GCHBs), and evaluated GCHB photoreactivity for degrading phenol and emerging persistent micropollutants in a 3D printed compound parabolic collector (CPC) reactor. The CPC photocatalytic system showed comparable performance with slurry reactors for sulfamethoxazole and carbamazepine degradation under simulated sunlight, and it maintained the performance for contaminant removal in real water samples collected from water/wastewater treatment plants or under outdoor sunlight irradiation. Global drinking water production was estimated for the CPC system, and it holds promise for small-scale sustainable water treatment, including, but not limited to, the production of high-quality potable water for single houses, small communities, rural areas, and areas impacted by natural disasters in both developed and developing countries.

One-step synthesis of TiO2 nanorod arrays on Ti foil for supercapacitor application.

Titanium dioxide (TiO2) nanorod arrays grown directly on Ti metal foil were prepared by a facile one-step hydrothermal method, in which the Ti foil serves as both substrate and precursor. The nanorods are tetragonal rutile single crystal with growth orientation along the [001] direction. The electrochemical properties of the TiO2 nanorod arrays were systematically investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy using a three-electrode system. As a result, the TiO2 nanorod arrays exhibit good areal specific capacitance and excellent cyclic stability by retaining more than 98% of the initial specific capacitance after 1000 cycles. In addition, a good flexibility of the Ti foil with TiO2 nanorod arrays was demonstrated by the stable electrochemical performance under different bending angles, which indicates that TiO2 nanorod arrays grown on Ti foil could be a promising electrode material for flexible supercapacitor application.