Denny’s research focuses on photocatalytic processes for sustainable fuels and chemicals production from solar energy. His work has concentrated on four interconnected programs.

Program 1. Photocatalyst Design: This program aims to accelerate the development of active, selective, and stable photocatalysts for solar-driven fuels and chemicals production. Key activities include optimisation of semiconductor materials with broad sunlight absorption and efficient charge separation and transfer, together with the design of ensemble active sites to enable cooperative catalysis. To rationally guide high-performance photocatalyst design and accelerate discovery, the program integrates computational approaches, including machine learning and first-principles calculations.

Program 2. Mechanistic Studies: This program investigates the mechanistic underpinnings of photocatalytic systems to establish key structure-activity and selectivity relationships. The work involves development and application of a diverse suite of advanced in situ characterisation techniques, complemented by kinetic modelling and first-principles calculations, to generate new insights into catalytic processes.

Program 3. System Engineering: This program focuses on the design, construction, integration, optimisation, and commissioning of scalable photoreactor system prototypes. The scope encompasses both solar- and artificial light-driven photoreactor development, supported by computational multiphase fluid dynamics modelling to simulate and optimise reactor performance and design.

Program 4. Techno-Economic Assessment: This program aims to establish an open-source techno-economic feasibility framework for emerging energy and chemical conversion processes, including photocatalysis. The framework is designed to evaluate the viability of new materials and process systems, with the overarching goal of accelerating translation by identifying key factors governing efficiency, scalability, and cost-effectiveness.