Professor Keith Ho’s wonderful passion for scientific research

Professor Keith Ho Wing-kei received his BSc and PhD in Chemistry from The Chinese University of Hong Kong, and was awarded post-doctoral fellowships in Hong Kong and Canada. He joined the Department of Science and Environmental Studies, EdUHK in 2012.

He has a broad range of research interests, including environmental remediation, nanotechnology, solar photocatalysis, air pollution control, indoor air quality and science education.

In 2019 and 2020, Professor Ho was on Stanford University’s list of the world’s top 2% of scientists. For four consecutive years from 2018 to 2021, he has been named in the list by Clarivate Analytics as a Highly Cited Researcher in the world. 

Professor Ho is an active researcher with an h-index of 82. He has had over 190 papers published in international journals, which have been cited about 18,000 times. Almost half of his papers are ranked in the top 5% of their respective disciplines.

In this issue of FLASS FORWARD, Professor Ho shares with us his passion for doing scientific research. He also talks about how to tackle environmental crises, whether being a scientist is a lonely business, and the importance of science education. 

A: My major research interest is in the area of materials science. The prime objective of my research is to find out new types of photocatalysts that are more effective in degrading toxic chemicals in water, decomposing air pollutants, and killing bacteria.

My research team studied a new photocatalytic material called graphitic carbon nitride. This new photocatalytic material consists of only carbon and nitrogen, which is metal-free and non-hazardous. Compared to traditional photocatalysts such as titanium dioxide, which can only be activated by UV light, the novel photocatalyst can have photocatalytic reactions activated by visible light, such as daylight or indoor lighting. With this technological breakthrough, even LED lighting, which is more energy-saving and environmentally friendly, can be used as a light source for photocatalysis.

A prototype of a portable air purifier

In addition, the new LED-activated graphitic carbon nitride photocatalyst — with an expected lifespan of one year — is capable of removing 90% of air pollutants, such as nitrogen oxides, and deactivating bacteria. The new material’s synthesis and fabrication technology allows the material to be readily coated on a surface. A thin coat of the material applied to construction materials, household wares and hospital facilities will add an air purification feature. That means that even flooring, ceilings, interior walls and household appliances may have a built-in air cleaning function. Our research also demonstrates that the new material can be used in portable air purifiers as well.

A: There is a strong consensus reached among scientists, government leaders and the commercial sector today that air pollution has become a common enemy of human beings, demanding immediate action on our part. According to World Health Statistics 2022, almost the entire world population (99%) breathes polluted air containing unhealthy levels of fine particulate matter and nitrogen dioxide, causing an estimated 7 million deaths across the globe every year where developing countries account for the vast majority of the fatalities.

Nitrogen oxides (NOx), a collective term for different kinds of nitrogen oxides but mainly composed of nitric oxide (NO), are generated by vehicles, factories and thermal power plants. Inhalation of nitrogen oxides causes damage to human lung tissue and contributes to secondary air pollution through the formation of photochemical smog, haze and acid rain. When nitrogen oxides react with volatile organic compounds (VOCs) in the presence of sunlight, ozone is created, which itself is an air pollutant. Breathing in ozone can harm people’s health.

On mainland China, coal burning and vehicle emissions have caused serious pollution problems. Over the years, the Chinese government has made impressive improvements in cutting sulfur dioxide (SO₂) emissions and particulate-matter pollution (PM 2.5). However, the emission levels of other pollutants, including NOx and ozone, remain unchanged.

We need an effective way to address these problems. Photocatalytic oxidation (PCO) is one of the best-known approaches to decomposing NOx at room temperature and ambient pressure. By removing air pollutants through photocatalytic oxidation, the LED-activated graphitic carbon nitride photocatalyst developed by my research team could effectively reduce the risk of people inhaling toxic materials.

In a broader sense, there are three approaches to tackling air pollution, or any form of pollution in general. The first is controlling the pollutant emissions from sources like electricity power plants, vehicles and factories through disincentives and regulatory frameworks. The second is what scientists like me are doing; that is, collecting and analysing related data through environmental sampling and conducting innovative and novel scientific research studies that provide solutions to challenging environmental problems.

Environment education is the third approach. Through educating our next generation about the limits of Mother Nature and the importance of conserving our environment, we can change their habits. By changing their way of life, we can create a more sustainable society in which people walk more, purchase less and consume fewer resources. They can create a society where less energy is consumed and less emissions are churned out.

Before I joined EdUHK, I spent most of my time on the second approach. At EdUHK, I have more chances to promote environment education to all stakeholders in the area of education, including schools, teaching staff, students and parents. I believe that promoting awareness and teaching the right attitudes to have as well as what actions are appropriate among students regarding environmental and sustainability issues can help them develop a sense of responsibility to care for our planet.

This has enlightened me to the fact that environment education might be the most effective means to tackle the problem after all and in 2022, I joined green group Friends of the Earth (HK) as a member of its Board of Governors, working with other devoted professionals to promote environmental education for our young generation and bring real change to our environment.

 

A: I began doing scientific research more than 20 years ago. In these two decades, I sometimes needed to work ridiculous hours. I remember at one of the research projects done during my doctoral studies, I needed to use an electronic microscope to take high-resolution images for my samples. Because the equipment was very sensitive to even small movements, I needed to carry out the experiment after midnight, when road traffic outside the laboratory had ground to a halt, to reduce the environmental impact on my measurements.

I recall that several years ago an issue of Harvard Business Review* did a survey on workplace loneliness among Americans, and the result pointed out that legal practitioners, research scientists and engineers topped the list of the most lonely workers. I admit that when one becomes a scientist, it is likely they end up a little lonely. That said, even though many scientists need to work for long hours at the laboratory alone, and even though they may feel a bit of loneliness for that, I personally don’t feel that I am lonely. As a scientist, I always view myself as connected with a bigger scientific community. I have a conviction that my discovery will form part of a bigger invention that will change the world.

Being a scientist might be a bit lonely, but I am certainly not alone. Besides the encouragement I get from being part of the scientific community, I find huge satisfaction in discovering things previously unknown to the world. To start your research work from scratch is simply fascinating. You start your research project by flipping through literary reviews, identifying a question you want to answer, and narrowing it down to an area where your research is focused on. Then you spend years venturing out to the laboratory, gathering and analysing data, drawing conclusions and waiting for that “Eureka!” moment of discovery.

The process of incubating a research idea, collecting data, converting the research findings into a paper, sending the paper to journal reviewers, and amending and finally publishing your papers can be long, but rewarding and thought-stimulating. When your paper is cited by your peers and gets recognition in the field, you feel an enormous sense of accomplishment.

A: In the first few years of my research career, I could only engage myself in research projects that guaranteed results within a few years in order to meet the pressure of publishing papers. Now I have bigger leverage to conduct more fundamental research projects that need 10 years or even longer to yield results. Fundamental research often surrounds problems that scientists have spent many years trying to solve but are still short of a definite answer. These are scientific research topics for which one can hardly guarantee achieving a result within the span of a few years. But a breakthrough in such research can mean a milestone in scientific discovery.

Another change to my research work is that I now enjoy greater flexibility when carrying out cross-disciplinary research projects, which requires collaborative work with engineers and scientists of other fields.

A: First of all, you need to be responsive to new discoveries. You have to change your approach when unexpected results occur. Secondly, you need to be patient. Finding a new approach and a better way to resolve an age-old puzzle is often the result of long hours of reading research articles, consulting expert advice and thinking. Thirdly, you need determination and perseverance. I have mentioned that for ground-breaking research, you have to commit yourself to your research for more than a decade, albeit only for a small step forward. It is somewhat similar to running a marathon.

A: At FLASS, I am responsible for three kinds of work: teaching, research and science education. Among them, promoting science education is a relatively new area to me.

I think science education is not only about knowledge. After graduation, people will sooner or later forget the subject knowledge. But through science education, we cultivate in people the ability to use empirical tests to verify a theory, a discerning attitude to carry out a justifiable comparison, and a scientific and critical mind to make a valid conclusion. People can benefit from these abilities and attitudes for a lifetime.

I always use how to fix a faulty torch as an example. When a torch is not functioning, it might be due to a worn-out battery, or because the polarity of the batteries are switched, or because of a broken light bulb. To find out the reason, we need to either change the battery, switch the polarity or replace the light bulb with a new one, with each step done one at a time to keep the other factors unchanged. This approach actually involves scientific thinking.

In recent years, the government has put in a lot of resources to promote STEM, STEAM (with the A representing "Arts") and even STREAM (with the R representing "Reading and wRiting") education. Some secondary schools even employ PhD graduates to teach science subjects. Many local schools have implemented a sophisticated system, employing many resources in promoting science education. I find this very encouraging. I have been a member of judging panels in primary or secondary school science competitions many times. I have observed that knowledge about STEM among Hong Kong students is rising. That is equally encouraging, too.

Science education is important in teaching our next generation to have a hard knowledge of science and logical thinking. More importantly, I believe science education can lead to habitual changes. The more people are enlightened about the impact of their daily life on the environment, the more likely we are able to trigger a chain of change of habits.

*Note: “America’s Loneliest Workers, According to Research”, Harvard Business Review, March 19, 2018.