One of the most significant global challenges for humans is environmental pollution. The technology to control this problem is the utilization of semiconductors as photocatalysts. In the current study, iron-doped titania nanotubes (Fe/TiNTs) with increased photocatalytic effect were synthesized via a modified hydrothermal method. The products were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy (TEM), gas adsorption, electron spin resonance (ESR) and UV–Vis diffuse reflectance spectroscopy (DRS). TEM results indicated that Fe/TiNTs have a tubular and uniform structure with an average outer diameter of 23–48 nm and length of 10–15 µm. ESR and DRS revealed that Fe³⁺ ions were successfully introduced into the TiNT structure by replacing Ti⁴⁺ ions. An enhanced light absorption in the range of 400–600 nm additionally indicated successful doping. The band gap was narrowed as iron wt% was increased. The photocatalytic activity was evaluated by the degradation of methyl orange (MO) in the presence of Fe/TiNTs and TiTNs by monitoring the degradation of MO under UV light irradiation. An acceleration on the hydration of Portland cement was observed in the presence of 2.0 wt% Fe/TiNTs. Fe/TiNTs can be used as a nanomaterial in cement-based building materials to provide self-cleaning properties to the surface of concrete even in indoor environments.

An electroless chemical reduction produced a self-supported phosphite-doped cobalt boride electrocatalyst with superior hydrogen evolution activity. Its unique structure and tuned cobalt active sites significantly boost water splitting efficiency.

Targeted phase engineering of nanomaterials through non-equilibrium synthesis strategies provides a rich platform for the development and tuning of nanostructured catalysts with outstanding properties and life-time. Unconventional phases or even complex heterostructures play a crucial role in the performance of catalysts for efficient water electrolysis. By utilizing a controlled, iterative reduction synthesis route, a tailored binder-free cobalt boride-phosphite electrode (CoxB-[0.2]P-O) with mixed crystalline-amorphous phases is developed. The tailored cobalt chemistry, hierarchical morphology and mixed phases synergistically enhance the catalytic activity for hydrogen evolution reaction (HER). Those electrodes exhibit platinum-like HER performance with an overpotential of 33 mV at the standard current density of 10 mA cm-2, with excellent intrinsic kinetics and enhanced electron transfer in an alkaline 1M KOH electrolyte. Comprehensive microstructure and spectroscopic analyses proved the success of the one-pot strategy to modulate the chemistry of cobalt by incorporating boron and phosphite. Moreover, the tailored formation of nanostructures with locally varying morphology by the co-existence of amorphous and crystalline phases on the nanometer scale is confirmed. This approach facilitates the rational design for tuning the metal boride-based catalysts’ activity for hydrogen evolution by tailored chemistry of the metal active centers and thus the phase engineering of similar nanomaterials while avoiding the necessity of any post-synthesis thermal treatment processes.