High-Performance Artificial Photosynthesis Without Noble Metals

An efficient catalyst that does not make use of expensive metals such as platinum could help make hydrogen generation economical.

AsianScientist (Sep. 21, 2015) – Scientists have designed an catalyst which can split water into hydrogen with blue light. The results, published in Energy and Environment Science, showed a remarkable yield of hydrogen at a relatively low cost.

As fuel shortages become more serious, developing renewable energy sources has become an urgent affair for both scientists and governments. Hydrogen, with its high energy density and nontoxic product, is an ideal alternative to existing greenhouse gas-generating sources.

Unfortunately, obtaining hydrogen is either inefficient or expensive, limiting the commercial applications of hydrogen fuel. Another bottleneck is the low yield of existing catalyst systems, hampered by the nonuniform distribution of catalyst and cofactor which cut down the lifetime of the photocatalyst.

A research team led by Professor Du Pingwu at the University of Science and Technology of China, Chinese Academy of Sciences, aimed at cutting down the cost by developing a photocatalyst system using only earth-abundant elements.

Existing photocatalysts use noble metals such as platinum to absorb the free electrons generated when the semiconductor material is excited by light. Instead of platinum, Du and his team used the phosphide transition metal nickel phosphide (Ni2P), which, like platinum, can also promote the separation of electron and hole in the semiconductor material.

To ensure high stability and a large surface area, the researchers anchored the crystalline Ni2P onto a one-dimensional cadmium sulfide semiconductor layer using a solvothermal reaction.

When the system is excited at 450nm (blue light), the apparent yield reaches about 41 percent, with one milligram of material producing 1,200 µmol hydrogen per hour. The noble metal-free system also achieved a high turnover number of 3,270,000 reactions in 90 hours.

With its high efficiency and low cost, Du’s system has the potential to satisfy increasing global demand for clean energy while also addressing the problem of pollution. Their work paves a way for the generation of clean, renewable energy.

The article can be found at: Sun et al. (2015) Extraordinarily Efficient Photocatalytic Hydrogen Evolution in Water Using Semiconductor Nanorods Integrated with Crystalline Ni2P Cocatalysts.


Source: Chinese Academy of Sciences; Photo: Luis Romero/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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