OICC Press Iranian Journal of Catalysis 2345-4865 14 3 2024 07 01 Efficient photocatalytic esterification of waste cooking oil over empty fruit bunches ash-supported TiO2 10.57647/j.ijc.2024.1403.25 EN Siti Fadhilah Ibrahim Faculty of Applied Sciences, University Technology MARA Pahang, Bandar Tun Abdul Razak Jengka, Pahang, Malaysia 0009-0004-3941-8583 Norshahidatul Akmar Mohd Shohaimi Advanced Biomaterials and Carbon Development Research Group, Faculty of Applied Sciences, University Technology MARA, Shah Alam, Selangor, Malaysia 0000-0002-1626-8277 Zul Adlan Mohd Hir Faculty of Applied Sciences, Universiti Teknologi MARA Pahang, Bandar Tun Abdul Razak Jengka, Pahang, Malaysia 0000-0001-5347-0186 Mohd Sufri Mastuli School of Chemistry and Environment, Faculty of Applied Sciences, University Technology MARA, Shah Alam, Selangor, Malaysia 0000-0002-0409-8987 Taufiq Yap Yun Hin Catalysis Science and Technology Research Centre (PutraCAT); Faculty of Science, University Putra Malaysia, UPM Serdang, Selangor, Malaysia 0000-0002-3994-6720 Mohd Lokman Ibrahim School of Chemistry and Environment, Faculty of Applied Sciences, University Technology MARA, Shah Alam, Selangor, Malaysia 0000-0003-3096-2991 Journal Article 2024 07 01 Biodiesel production from waste cooking oil (WCO) holds promise as a renewable and sustainable energy source. However, high levels of free fatty acids (FFAs) in WCO require efficient pretreatment before transesterification. Utilizing solar energy for heterogeneous catalytic reactions offers an alternative to thermal-driven processes. TiO2EFBA, synthesized via the wet impregnation method, exhibits distinctive physicochemical properties confirming the successful incorporation of titanium dioxide (TiO2) onto the metal oxides of empty fruit bunches ash (EFBA), thereby enhancing the catalyst’s performance and stability. Results showed that TiO2EFBA exhibits superior FFA conversion compared to TiO2 alone. Under optimized reaction conditions, employing 4 wt% TiO2EFBA catalyst, 20:1 methanol to oil molar ratio, and 2 h reaction time at room temperature under Ultra Violet (UV) light, achieves a remarkable 78% conversion rate of FFAs in WCO. Mechanistic investigation reveals the crucial role of electron/hole (e−/h+) species in reducing FFAs by suppressing the e−/h+ mechanism. Notably, TiO2EFBA facilitates easy separation and can be reused for 10 cycles, demonstrating its stability as a heterogeneous photocatalyst. Research Hightlights Successful reduction of high free fatty acid (FFAs) content of waste cooking oil (WCO) from 12.4 wt% to 2.7 wt% using semiconductor photocatalyst (TiO2EFBA) achieved up to 78% conversion. TiO2EFBA is highly active heterogeneous semiconductor photocatalyst in esterification of WCO under 365 nm UV light. TiO2 doped EFBA reduce the bandgap energy of TiO2 and increase the performance of photocatalyst. EFBA can serve as trapping agent by capture the electron-holes pair from recombination and enhanced the charge carrier separation. TiO2EFBA can reused up to 10 times without reduction of catalytic performance.