Indonesia is a tropical country blessed with sunlight all year round. Therefore, any technologies involving sunlight utilization are highly relevant to Indonesia. One of such promising technologies is photocatalysis. Photocatalysis is acceleration of a chemical reaction due to the presence of catalyst and light. Triggered by this situation, Center of Excellence on Heterogeneous Photocatalyst Materials (PhotoCAT) was established by Dr. Hanggara Sudrajat in Universitas Jember to perform innovative researches on heterogeneous photocatalysis for energy and environmental applications. PhotoCAT is the first research center in Indonesia specifically focused on photocatalysis science and technology. The ultimate goal of PhotoCAT is to become the core laboratory for photocatalysis research in the country. Research standards at PhotoCAT are internationally recognized to be at the cutting edge of scientific discovery. The publication rate of PhotoCAT is approximately 7 papers annually; about 90% of this in top-tier (Quartile 1) journals. Currently, PhotoCAT is collaborating with various foreign institutions in:
- Germany (Max Planck Institute for Polymer Research; Karlsruhe Institute of Technology)
- Italy (University of Milano-Bicocca)
- Japan (Kobe University; Chiba University; Hiroshima University; Tokyo Institute of Technology; Nagoya Institute of Technology)
- Thailand (Chulalongkorn University; Thammasat University; Synchrotron Light Research Institute)
- Vietnam (Ton Duc Thang University)
- PhotoCAT is always pleased to establish a new research collaboration with both international and domestic groups working on photocatalysis and related topics.
Dr. Hanggara Sudrajat
The main topic of PhotoCAT includes the development of inorganic hybrid nanostructures for energy and environmental applications via heterogeneous photocatalysis. Various novel photocatalysts have been developed. Synchrotron-based techniques, such as XANES, EXAFS, soft-XAS, XPS, XFH, and UPS, are involved for characterization (Figs. 1 and 2). Use of such state of the art techniques leads to new, fundamental insights into structure–photoactivity relationship for further rational photocatalyst design.
Fig. 1 Structural elucidation of metal oxides with synchrotron techniques.
Fig. 2 X-ray absorption study of local structure of Cu species on Bi2O3.
PhotoCAT is now focusing on photocatalytic hydrogen generation through water splitting since this is one promising route to harvest clean and sustainable energy. Perovskite-structured oxides (ABO3) are extensively employed due to their high photocatalytic activity. Especially NaTaO3 (Fig. 3), it is known to have a quantum efficiency of 56% under UV light when being doped with La. This is the world-record efficiency for photocatalytic water splitting. Unfortunately, while metal-doped NaTaO3 has offered astonishing developments in engineering for artificial photosynthesis, questions in science remain to be answered. The mechanisms behind doping-induced enhancement of water splitting efficiency is unknown, and the decisive properties of dopant atoms in relation with photoexcited electrons and holes also remain nearly unexplored. Without understanding science of the highly efficient photocatalysts, how and why water splits on properly doped NaTaO3, proper research direction can never be obtained.
Fig. 3 Double doping of NaTaO3 with La as A-site dopant and transition metals as B-site dopants.
Besides metal oxide based photocatalysts, metal-free photocatalysts with gC3N4 and metal-free elemental photocatalysts such as red phosphorus, selenium, and sulfur are also being explored. The library of photocatalytic materials based on gC3N4 developed in PhotoCAT includes Na/gC3N4 (Fig. 4), Fe(III)/gC3N4, Zn(II)/gC3N4, and Ag(I)/gC3N4. They are extensively characterized by XANES and EXAFS, and mostly photoactive for the destruction of recalcitrant organic contaminants under UV-visible light.
Fig. 4 Na-doped gC3N4 photocatalyst for decomposition of recalcitrant organic compound.
Publications in Journals with IF and SJR
- Sudrajat, Superior photocatalytic activity of polyester fabrics coated with zinc oxide from waste hot dipping zinc, Journal of Cleaner Production, Accepted.
- Sudrajat and S. Babel, Role of reactive species on the photocatalytic degradation of amaranth by highly active N-doped WO3, Bulletin of Materials Science, In Press.
- Sudrajat, A one-pot, solid-state route for realizing highly visible light active Na-doped gC3N4 photocatalysts, Journal of Solid State Chemistry, Vol. 257, pp. 26-33, January 2018.
- Sudrajat, Chemical state and local structure of V species incorporated in δ-Bi2O3 photocatalysts, Journal of Materials Science, Vol. 53, pp. 1088–1096, January 2018.
- Sudrajat, Unprecedented ultrahigh photocatalytic activity of δ-Bi2O3 for cylindrospermopsin decomposition, Journal of Nanoparticle Research, Vol. 19, pp. 369, November 2017.
- Sudrajat, Template-free, simple fabrication of C/N-doped Bi2O3 nanospheres with appreciable photocatalytic activity under visible light, Superlattices and Microstructures, Vol. 109, pp. 229-239, September, 2017.
- Sudrajat and P. Sujaridworakun, Correlation between particle size of Bi2O3 nanoparticles and their photocatalytic activity for degradation and mineralization of atrazine, Journal of Molecular Liquids, Vol. 242, pp. 433-440, September, 2017.
- Sudrajat and P. Sujaridworakun, Insights into structural properties of Cu species loaded on Bi2O3 hierarchitectures for highly enhanced photocatalysis, Journal of Catalysis, Vol. 352, pp. 394-400, August, 2017.
- Sudrajat, Reducing agent-free formation of Cu(I) nanoclusters on gC3N4 for enhanced photocatalysis, Journal of Alloys and Compounds, Vol. 716, pp. 119-127, September, 2017.
- Sudrajat and P. Sujaridworakun, Low-temperature synthesis of δ-Bi2O3 hierarchical nanostructures composed of ultrathin nanosheets for efficient photocatalysis, Materials & Design, Vol. 130, pp. 501–511, September, 2017.
- Sudrajat, Cu(II)/Bi2O3 photocatalysis for toxicity reduction of atrazine in water environment under different light wavelengths, Environmental Processes, Vol. 4, pp. 439–449, June, 2017.
- Sudrajat and S. Babel, A novel visible light active N-doped ZnO for effective photocatalytic degradation of recalcitrant dyes, Journal of Water Process Engineering, Vol. 16, pp. 309-318, April, 2017.
- Babel, P.A. Sekartaji and H. Sudrajat, TiO2 as an effective nanocatalyst for photocatalytic degradation of humic acid in water environment, Journal of Water Supply: Research and Technology – Aqua, Vol. 66, No 1, pp. 25-35, February, 2017.
- Sudrajat and S. Babel, A new, cost-effective solar photoactive system N-ZnO@polyester fabric for degradation of recalcitrant compound in a continuous flow reactor, Materials Research Bulletin, Vol. 83, pp. 369-378, November, 2016.
- Sudrajat and S. Babel, Rapid photocatalytic degradation of the recalcitrant dye amaranth by highly active N-WO3, Environmental Chemistry Letters, Vol. 14, pp. 243-249, June, 2016.
- Sudrajat and S. Babel, Comparison and mechanism of photocatalytic activities of N-ZnO and N-ZrO2 for the degradation of rhodamine 6G, Environmental Science and Pollution Research, Vol. 23, pp. 10177-10188, May, 2016.
- Sudrajat and S. Babel, An innovative solar photoactive system N-WO3@polyester fabric for degradation of amaranth in a thin-film fixed-bed reactor, Solar Energy Materials and Solar Cells, Vol. 149, pp. 294-303, May, 2016.
- Sudrajat, S. Babel, H. Sakai and S. Takizawa, Rapid enhanced photocatalytic degradation of dyes using novel N-doped ZrO2, Journal of Environmental Management, Vol. 165, pp. 224-234, January, 2016.