In tropical countries like Singapore, solar energy remains one of the most viable sources of renewable energy for power generation. In 2020, Singapore achieved its solar deployment target of 350 megawatt-peak (MWp) in just the first quarter of the year. This represents an amount sufficient to power 60,000 households a year.

Leveraging on this practically inexhaustible source of energy is Professor Ho Ghim Wei, who integrates the unique properties of nanoparticles into novel solar-energy-based technologies to sustainably produce clean fuels, energy and water.

One research focus is on the synthesis of catalytic and interfacial heterogeneous nanostructures that are tailored to improve the efficiency of fuel production using solar energy. For example, Prof Ho has synthesised wurtzite cobalt(II) oxide nanorods with atomic zinc sites that exhibit highly efficient and stable photocatalytic activity toward carbon dioxide (CO₂) reduction. From this, methane gas is produced without the use of any sacrificial agents or photochemical sensitisers. Methane gas is cleaner than alternative fossil fuels when combusted.

Beyond CO₂ reduction, Prof Ho also looks into effective ways to produce clean water using solar energy. For example, she is developing a three-dimensional (3D) photothermal catalytic spherical isotopic evaporator, which enables the evaporation of interfacial water under solar irradiation, purifying the water in the process. In contrast to the conventional two-dimensional (2D) steam generators, which do not allow maximum absorption of solar energy at dawn and dusk, the spherical isotropic evaporator will always have a hemispherical surface facing the sun, thereby maximising the absorbance of solar energy throughout the day for improved water purification efficiency.