PhotoCAT – The Center of Excellence on Heterogeneous Photocatalyst Materials



Indonesia is a tropical country blessed with sunlight all year round. Therefore, any technologies involving sunlight as the energy source are relevant to Indonesia. One of such promising technologies is photocatalysis. Photocatalysis is the acceleration of a photoreaction in the presence of a catalyst; the so-called artificial photosynthesis. Based on this rationale, PhotoCAT – The Center of Excellence on Heterogeneous Photocatalyst Materials is established by Dr. Hanggara Sudrajat in the Department of Chemical Engineering, Universitas Jember to perform innovative researches on heterogeneous photocatalysis for solar energy conversion. The ultimate goal of PhotoCAT is to become the core laboratory for photocatalysis research in the region. Research standards at PhotoCAT are internationally recognized to be at the cutting edge of scientific discovery. PhotoCAT is extensively strengthening its research capacity, and hence is always pleased to establish new research collaboration with both international and domestic groups working on photocatalysis and related topics.


Research Topics

The main topic of PhotoCAT includes the development of inorganic hybrid nanostructures for making efficient use of light energy to evolve hydrogen and to reduce carbon dioxide, as well as for environmental purification to photomineralize refractory organic compounds via heterogeneous photocatalysis. A diverse range of metal oxides and carbon-based materials intended for artificial photosynthesis have been developed by PhotoCAT thus far. Synchrotron-based techniques, such as XANES, EXAFS, soft-XAS, XPS, XFH, and UPS, are involved for the characterization (Figs. 1 and 2). Use of such state of the art techniques leads to new, fundamental insights into the structure–photoactivity relationship for further rational catalyst design.

Fig. 1 Structural elucidation of metal oxides with synchrotron-based techniques

         Fig. 2 X-ray absorption study of local structure of Cu species on Bi2O3

At present, PhotoCAT focuses on photocatalytic hydrogen evolution through water splitting reaction, because it is one promising route to harvest clean and sustainable energy. The upcoming focus is the photocatalytic conversion of carbon dioxide into sustainable fuels, such as methanol. Regarding the material choices, perovskite-structured oxides (ABO3) are good options due to their high photocatalytic activity. Particularly NaTaO3, it is known to have a quantum efficiency of 56% under UV light when being doped with La. 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 not fully understood, and the decisive properties of dopant atoms in relation to photoexcited electrons and holes 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. In this regard, PhotoCAT is currently striving to clarify such critical issues using sophisticated techniques including XANES, EXAFS, XFH, and time-resolved spectroscopy. In addition, visible light sensitization of NaTaO3 through the scheme of charge compensated double doping with La and (mainly) d-block transition metals has also been being extensively studied. We are building a library of visible light active LaMO3-NaTaO3 solid solutions for artificial photosynthesis (Fig. 3). An example of such a promising photocatalyst system is NaTaO3 doubly doped with La and Fe. By employing XANES and EXAFS, we successfully clarify the occupation preferences of the dopants in the NaTaO3 host (Fig. 4).


Fig. 3 Library of visible light active LaMO3-NaTaO3 solid solutions for artificial photosynthesis


Fig. 4 Double doping of NaTaO3 with La and Fe

Principal Investigator

Dr. Hanggara Sudrajat,

“He likes very much the Schrödinger’s cat, a paradox formulated by Austrian physicist Erwin Schrödinger”



  1. Sudrajat, H., Dhakal, D., Kitta, M., Sasaki, T., Ozawa, A., Babel, S., Yoshida, T., Ichikuni, N., Onishi, H.

Electron population and water splitting activity controlled by strontium cations doped in KTaO3 photocatalysts

Under review

  1. Sudrajat, H., Ichikuni, N., Onishi, H.

Visible light responsive La- and Fe-codoped NaTaO3 photocatalysts: local structure around dopants

Under review

  1. Sudrajat, H., Kitta, M., Ichikuni, N., Onishi, H.

LaMnO3-NaTaO3 solid solution photocatalysts with strong visible light absorption

Under review

  1. Sudrajat, H., Ozawa, A., Yoshida, T., Ichikuni, N., Onishi, H.

La-doped KTaO3 photocatalysts for overall water splitting

Under review

  1. Sudrajat, H., Hartuti, S., Nguyen, T.K.

Lanthanum chromite for visible light-driven photocatalytic hydrogen evolution

Under review

  1. Sudrajat, H., Babel, S., Phanthuwongpakdee, J., Nguyen, T.K.

Local structure of iron oxide sensitizing Nb2O5 photocatalysts

Under review

  1. Sudrajat, H., Zhou, Y., Sasaki, T., Ichikuni, N., Onishi, H.

The atomic-scale structure of LaCrO3–NaTaO3 solid solution photocatalysts with enhanced electron population

Physical Chemistry Chemical Physics, 2019, 21, 5148-5157

  1. Sudrajat, H., Babel, S.

Loading of metallic silver onto ZnO for enhancement of electron population and photocatalytic activity

International Journal for Light and Electron Optics – OPTIK 183, 2019, 472-482

  1. Sudrajat, H., Thushari, I., Babel, S.

Chemical state and coordination structure of La cations doped in KTaO3 photocatalysts

Journal of Physics and Chemistry of Solids 127, 2019, 94-100

  1. Sudrajat, H., Hartuti, S.

Increased photocatalytic activity caused by B doping into BiVO4

Research on Chemical Intermediates 45, 2019, 2179-2195

  1. Sudrajat, H., Hartuti, S.

One-pot, solid-state loading of Zn into g-C3N4 for increasing the population of photoexcited electrons and the rate of photocatalytic hydrogen evolution

International Journal for Light and Electron Optics – OPTIK 181, 2019, 1057-1065

  1. Sudrajat, H., Hartuti, S.

Boosting electron population in δ-Bi2O3 through iron doping for improved photocatalytic activity

Advanced Powder Technology 20, 2019, 983-991

  1. Sudrajat, H., Babel, S.

Ultrahigh photoactivity of ZnO nanoparticles for decomposition of high-concentration microcystinLR in water environment

International Journal of Environmental Science and Technology 16, 2019, 695-706

  1. Sudrajat, H., Babel, S., Thushari, I., Laohhasurayotin, K.

Stability of La dopants in NaTaO3 photocatalysts

Journal of Alloys and Compounds 775, 2019, 1277-1285

  1. Sudrajat, H.

Evidence of improved electron-hole separation in Fe@g-C3N4 photocatalysts

Materials Research Express 5, 2018, 095501

  1. Sudrajat, H., Hartuti, S.

Structural properties and catalytic activity of a novel ternary CuO/gC3N4/Bi2O3 photocatalyst

Journal of Colloid and Interface Science 524, 2018, 227-235

  1. Sudrajat, H., Hartuti, S., Park, J.

A newly constructed photoactive system, Fe(III)-C/N-Bi2O3, for efficient visible light photocatalysis

Journal of Alloys and Compounds 748, 2018, 390-397

  1. Sudrajat, H.

Unraveling structural properties of Cu2O loaded on gC3N4 for enhanced photocatalytic hydrogen generation

Materials Research Express 5, 2018, 065519

  1. Sudrajat, H., Hartuti, S.

Easily separable N-doped ZnO microspheres with high photocatalytic activity under visible light

Materials Research Bulletin 102, 2018, 319-323

  1. Sudrajat, H.

Superior photocatalytic activity of polyester fabrics coated with zinc oxide from waste hot dipping zinc

Journal of Cleaner Production 172, 2018, 1722-1729

  1. Sudrajat, H.

A one-pot, solid-state route for realizing highly visible light active Na-doped gC3N4 photocatalysts Journal of Solid State Chemistry 257, 2018, 26-33

  1. Sudrajat, H.

Chemical state and local structure of V species incorporated in δ-Bi2O3 photocatalysts

Journal of Materials Science 53, 2018, 1088-1096

  1. Sudrajat, H., Babel, S.

Role of reactive species in the photocatalytic degradation of amaranth by highly active N-doped WO3 Bulletin of Materials Science 40, 2017, 1421-1428

  1. Sudrajat, H.

Unprecedented ultrahigh photocatalytic activity of δ-Bi2O3 for cylindrospermopsin decomposition Journal of Nanoparticle Research 19, 2017, 369

  1. Sudrajat, H., Sujaridworakun, P.

Low-temperature synthesis of δ-Bi2O3 hierarchical nanostructures composed of ultrathin nanosheets for efficient photocatalysis

Materials and Design 130, 2017, pp. 501-511

  1. Sudrajat, H.

Template-free, simple fabrication of C/N-doped Bi2O3 nanospheres with appreciable photocatalytic activity under visible light

Superlattices and Microstructures 109, 2017, 229-239

  1. Sudrajat, H., Sujaridworakun, P.

Correlation between particle size of Bi2O3 nanoparticles and their photocatalytic activity for degradation and mineralization of atrazine

Journal of Molecular Liquids 242, 2017, 433-440

  1. Sudrajat, H.

Cu(II)/Bi2O3 Photocatalysis for Toxicity Reduction of Atrazine in Water Environment under Different Light Wavelengths

Environmental Processes 4, 2017, 439-449

  1. Sudrajat, H., Babel, S.

A novel visible light active N-doped ZnO for photocatalytic degradation of dyes

Journal of Water Process Engineering 16, 2017, 309-318

  1. Babel, S., Sekartaji, P.A., Sudrajat, H.

TiO2 as an effective nanocatalyst for photocatalytic degradation of humic acid in water environment Journal of Water Supply: Research and Technology – AQUA 66, 2017, 25-35

  1. Sudrajat, H.

Reducing agent-free formation of Cu(I) nanoclusters on gC3N4 for enhanced photocatalysis

Journal of Alloys and Compounds 716, 2017, 119-127

  1. Sudrajat, H., Sujaridworakun, P.

Insights into structural properties of Cu species loaded on Bi2O3 hierarchical structures for highly enhanced photocatalysis

Journal of Catalysis 352, 2017, 394-400

  1. Sudrajat, H., Babel, S.

A new, cost-effective solar photoactive system N-ZnO@polyester fabric for degradation of recalcitrant compound in a continuous flow reactor

Materials Research Bulletin 83, 2016, 369-378

  1. Sudrajat, H., Babel, S.

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 149, 2016, 294-303


  1. Sudrajat, H., Babel, S.

Comparison and mechanism of photocatalytic activities of N-ZnO and N-ZrO2 for the degradation of rhodamine 6G

Environmental Science and Pollution Research 23, 2016, 10177-10188

  1. Sudrajat, H., Babel, S.

Rapid photocatalytic degradation of the recalcitrant dye amaranth by highly active N-WO3

Environmental Chemistry Letters 14, 2016, 243-249

  1. Babel, S., Arayawate, S., Faedsura, E., Sudrajat, H.

Production of biodiesel from waste cooking oil using transesterification with the KOH on carbon support from waste material and egg shell as the Catalyst

Environment and Natural Resources Journal 14, 2016, 60-68

  1. Sudrajat, H., Babel, S., Sakai, H., Takizawa, S.

Rapid enhanced photocatalytic degradation of dyes using novel N-doped ZrO2

Journal of Environmental Management 165, 2016, 224-234