Identifying and overcoming catalytic bottlenecks in CuO-based oxide systems for energy and environmental applications

Abstract

This chapter introduces two interconnected global challenges: the growing demand for sustainable energy conversion and the persistent problem of environmental pollution arising from industrial effluents. It highlights the limitations of fossil-fuel–based technologies and conventional wastewater treatment methods, underscoring the need for advanced catalytic strategies that operate efficiently under mild, sustainable conditions. In this context, solar-driven photocatalysis and electrochemical energy conversion are discussed as promising approaches for pollutant degradation and renewable energy technologies. This chapter outlines the experimental procedures employed for the synthesis, processing, and characterization of CuO-based materials investigated in this thesis. Emphasis is placed on reproducibility, compositional control, and scalability of the adopted synthesis routes. Pristine and transition-metal-doped CuO materials were synthesized using sol–gel and hydrothermal methods under carefully controlled conditions. This chapter investigates the synthesis, physicochemical properties, and photocatalytic performance of aliovalent Al3+-doped CuO as a visible-light-active catalyst for the degradation of organic pollutants. A controlled series of Cu1-xAlx O1+δ compositions was synthesized using a scalable sol–gel method to systematically examine how non-redox Al3+ substitution modulates the electronic structure, defect chemistry, and surface reactivity of CuO. In Chapter 3, Al3+-substituted CuO photocatalysts exhibited enhanced photo-Fenton-like degradation of organic pollutants under low-power illumination, where reaction temperature emerged as an influential but coupled parameter alongside dopant-induced electronic effects. To isolate and clarify the intrinsic role of temperature on photocatalytic kinetics, the present chapter focuses on undoped, morphology-engineered CuO nanosheets as a simplified model system. Building upon the temperature-dependent photo-Fenton-like degradation behaviour of pure CuO nanosheets (Chapter 4) and the defect-engineering framework established for Al3+-substituted CuO (Chapter 3), this chapter investigates the role of redox-active Fe3+ substitution in modulating the photocatalytic degradation of organic pollutants.