Ustc photocatalytic hydrogen production for new catalyst research progress
Recently, Wu Changzheng research group, a professor at the university of science and technology of China and chang chun team cooperation, to develop a new water soluble small molecule cocatalyst to speed up the light hole transfer, implements the photocatalytic hydrogen production performance improved, so as to get rid of the current widespread use of the precious metal catalyst promoter puts forward a new solution.Related research achievements on October 21, published online in nature communications (2015,6,8647 NatureComm.).
Convert the solar energy efficiency of low density for storage of chemical energy is an important way of promoting the development of renewable energy.However, the living carrier of composite seriously limits the artificial light conversion efficiency of catalytic system, how to maximize light born carrier separation become important challenges to improve the efficiency of photocatalysis.Load type of precious metals is widely considered to be high efficient catalyst promoter, but precious metals as a solid catalyst usually leads to limited contact area, high costs at the same time also greatly limit its large-scale application.
According to these challenges, Wu Changzheng team broke through the traditional view is efficient cocatalyst mostly focused on the limitations of solid-phase precious metals, for the first time found that water soluble small molecule trifluoroacetic acid (TFA) is a kind of new and efficient molecular cocatalyst。Innovative, they noticed reversible REDOX electricity of TFA existence, and in the photocatalytic environment show that the high degree of reversibility, the carrier for the transmission of light students provides a new train of thought.Molecular cocatalyst TFA, through their REDOX reaction to achieve the fast free radicals between molecules, accelerated the rapid transfer of the cavity.In potassium niobate two-dimensional nanomaterials, on the basis of high specific surface area advantage, successfully raised photocatalytic hydrogen production performance by 32 times.Nuclear magnetic resonance (NMR), element analysis and in situ electron spin resonance characterization confirmed potassium niobate the light of the valence band hole and the adsorption of TFA anion reaction can produce highly reactive free radicals TFA;TFA free radicals transfer holes to methanol at the same time, so as to realize the potassium niobate electronic - hole in two dimensional nanomaterials catalytic systems for efficient separation。Its collaborators chang chun group USES the super fast transient absorption spectra and steady/transient fluorescence spectrum measurements, depicts the model system is closely related to the hole trap state and electron trap state light carrier dynamics behavior and mechanism, which proved the rationality of the water-soluble small molecule cocatalyst strategy and effectiveness.Ultrafast dynamics analysis shows that TFA after adding potassium niobate nano piece light electronic life expectancy increased nearly three times, revealed a small molecule cocatalyst induced hole transfer and electronic - hole of separation is to improve the photocatalytic performance of the system root cause。Small molecule cocatalyst strategy is put forward, is expected to get rid of the traditional system of precious metal catalyst promoter, for the design of cheap, efficient photocatalytic system opened up new ways。
This work obtained the national science foundation, ministry of science and technology, Chinese academy of sciences, energy and materials chemistry collaborative innovation center, quantum information and quantum collaborative innovation center at the forefront of science and technology support.
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