The method of electrochemical preparation of nanoporous gold, which, because of the unique bactericidal and bacteriostatic properties as well as corrosion resistance, is now the subject of intensive research in various research centres worldwide, is an invention of Dr. Bożena Łosiewicz and her colleagues from the Institute of Materials Science of the University of Silesia in Katowice.

Research on obtaining nanopores (nanoopenings on the order of 10 to the minus 9 meters) in gold took three months. "We are now conducting advanced research on characterization of nanoporous gold in dentistry. We are examining its corrosion resistance in the case of dental implants implanted in patients" - said Dr. Łosiewicz.

She added that research on the prediction of corrosion rate is carried out in vitro in simulated body fluids, including urine, plasma, blood, saliva. Nanometer-sized pores in gold can cover the entire surface of the implant.

"The hardest part after implantation are the first 2-3 days, when the body recognizes the implant as a foreign body and tries to reject it. This can lead to infection, inflammation. The surface of the implant coated with a nanometer-sized pores in gold results in a milder osseointegration of the implant" - said Dr. Łosiewicz. She noted that the research team spreads antibiotics, anti-inflammatory, antithrombotic drugs on the surface of nanopores.

The use of nanoporous gold, as the expert emphasised, can be very broad and many universities in the world are already looking for its possible applications not only in medicine, but also in the hydrogen energy sector.

The search for new alternative sources of renewable energy continues and hydrogen may be the fuel of the twenty-first century. Prospects for the practical use of hydrogen as the most eco-friendly energy carrier can be presented, as Łosiewicz added, on an example of the car designed and made in the US, in which traditional fuels (gasoline, diesel, oil) have been replaced by hydrogen.

Silesian scientists have also decided to follow the trail of renewable energy sources. "We live in a time when emissions to the environment lead to serious pollution, including carbon oxides, sulphur oxides. It is difficult to eliminate them, when the number of cars continues to increase. That is why we want to use alternative fuels. In Upper Silesia research is currently underway into the use of hydrogen gas as a fuel" - she added.

But there is a problem, as Łosiewicz pointed out, with using hydrogen gas as car fuel. "You have to process the gas chemical energy into electrical energy. This is the task of fuel cell consisting of electrodes (anode and cathode). Our invention can be used to make such electrodes from nanoporous gold. In such a porous material, hydrogen could be separated and stored faster" - she said.

Moreover, as she pointed out, "With a fuel cell, the only product of combustion is water, which means that only water vapour is emitted into the environment".

The invention was presented in October at the International Warsaw Invention Show IWIS 2015 and won the IWIS 2015 Gold Medal in the category Electronics and Power, as well as the Special Prize of the Ministry of Science and Higher Education.

The concept of hydrogen car designed and made in the US is based, as the expert added, on the application of fuel cell with polymeric proton exchange membrane, which can work as an electrolyser that uses solar energy to split water to hydrogen gas and oxygen, or a fuel cell using stored hydrogen to power the electric motor and move the car. In real-life conditions, cars with built-in hydrogen fuel cell have a range of 200-400 km on 4 litres of hydrogen as a fuel.

Instead of traditional gas tanks, the car has a hydrogen storage tank and a fuel cell that converts the chemical energy of hydrogen into electricity supplied to an electric motor.

Katarzyna Piotrowiak (PAP)

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