Improved solar light stimulated charge separation of g-C3N4 through self-altering acidic treatment

Significance Statement

The process of identifying more efficient as well as green photocatalysts for several environmental remediation and energy conversion processes have received global attention in the last few years. The transformation of the renowned semiconductor catalysts, titanium oxide to the recently synthesized metal free semiconductor, graphitic carbon nitride had exhibited great progress. Recently, this photocatalyst has received significant research attention owing to its distinctive features such as anti-photo corrosion, chemically stable, low cost, and contains most abundant elements. Unfortunately, graphitic carbon nitride suffers from low surface area as well as high recombination rates leading to deprived photocatalytic efficacy.

A number of modifications have been done to enhance the underlying photocatalysis of the bulk graphitic carbon nitride, which include doping with non-metal/metal and other semiconductors and copolymerization.  In addition to enhance the synthesis of new green synthesis photocatalysts, researchers should reconsider on doping modification method. Self-modification of the graphitic carbon nitride is a modification process that has neither been least nor not considered. Recently, graphitic carbon nitride with alkali treatment has developed exhibiting considerable improvement in extending the longevity of the electron hole pairs excited under visible light irradiation. The enhancement in photocatalysis was developed by the decomposing RhB dye.

In addition, porous graphitic carbon nitride with several acidic templates that indicate high performance on degenerating Rhodamine B and phenol has been modified. Unfortunately, this self-altering method of graphitic carbon nitride refinement for solar photocatalysis has not been attempted. Professor Kah Hon Leong and colleagues implemented acid treatment to treat graphitic carbon nitride nanostructured by a direct synthesis method. The proposed treatment enhanced photoactivity of graphitic nitride and was reflected in the removal of recalcitrant organic pollutant, under direct sunlight. Their research work is published in peer-reviewed journal, Applied Surface Science.

The authors prepared photocatalysts that were analyzed via a sustainable photocatalysis method using sunlight as a source of radiation and selecting a poor photosensitive pollutant compound, Bisphenol A. They conducted the experiments under a bright and intense sunlight. In addition, the authors performed dark experiments for about 3 hours to realize adsorption and desorption equilibrium. These experiments were done before solar photocatalysis experiment. Moreover, a control experiment was done in the absence of a photocatalyst.

The authors were able to prepare self-alteration to bulk graphitic carbon nitride via an elementary and direct preparation path with acidic treatment in a bid to extend the longevity of its charge carriers. The researchers recorded a complete removal of the Bisphenol A in 225 minutes by the treated graphitic carbon nitride under intense sunlight as compared to pure graphitic carbon nitride. The improvement could be referenced to the blue shift and delayed the rate of recombination of electrons and holes.

In addition, it influenced the development of active superoxide anion radicals, which were responsible for the photocatalytic activity. The authors then proposed a mechanism of electrons flow that would play a critical role in identifying self-enhancement photocatalysts, which would be stable under intense solar energy.

The outcomes of their study would be important for the increased demand for solar light sensitive photocatalysts that are necessary in satisfying the demands of complicated environmental pollutants particularly in enhancing a sustainable environment.

Improved solar light stimulated charge separation of g-C3N4 through self-altering acidic treatment. Renewable Energy Global Innovations

About the author

Dr Kah Hon Leong received his Ph.D in Environmental Engineering from University of Malaya in 2015. Currently, he is an Assistant Professor at Universiti Tunku Abdul Rahman, Malaysia. His research focuses on design and synthesis of highly improved solar light driven nanomaterials for sustainable environmental and energy applications.

About the author

Mr.Ping Feng Lim studied Environmental Engineering from Universiti Tunku Abdul Rahman, Malaysia and graduated in 2016. Currently, he is doing his master degree with Dr Kah Hon Leong on the subject of perovskite photocatalysts for sustainable environmental remediation.

About the author

Dr. Lan Ching Sim received her Ph.D in Environmental Engineering from University of Malaya in 2015. Currently, she is an Assistant Professor at Universiti Tunku Abdul Rahman. Her research interests include the developing and synthesis of semiconductor, plasmonic and carbon materials photocatalysts for water and energy applications.

About the author

Mr.Varun Punia is pursuing Bachelor of Technology in Civil Engineering at Indian Institute of Technology Roorkee, India. He has worked at the Environmental Nanotechnology Research Laboratory, Department of Civil Engineering, University of Malaya, Malaysia during his summer internship visit in 2016.

About the author

Dr. Pichiah Saravanan received doctoral degree in Chemical Engineering from Indian Institute of Technology Guwahati, India. Presently he is Associate Professor in Department of Environmental Science and Engineering, Indian Institute of Technology (ISM) Dhanbad, India and also heading the Environmental Nanotechnology research laboratory.

He was key founder of “Environmental Nanotechnology” research laboratory at Department of Civil Engineering, University of Malaya, Malaysia where he served as Senior Lecturer between 2010 to 2016. He is fascinated in developing nanomaterials for sustainable environmental remediation’s and energy applications.


Kah Hon Leong, Ping Feng Lim, Lan Ching Sim, Varun Punia, Saravanan Pichiah. Improved solar light stimulated charge separation of g-C3N4 through self-altering acidic treatment. Applied Surface Science


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