Recycling of carbon dioxide to renewable fuels by photocatalysis: Prospects and challenges

Carrier dynamics and the role of surface defects: Designing a photocatalyst for gas-phase CO 2 reduction

“…To better understand the complex processes apparent in the TA spectra, we used a multiexponential decay function to model the different charge carrier relaxation dynamics in the material. Each data set, collected with a single pump wavelength, incident pump fluence, and a series of probe wavelengths (λ), was fit to a sum of exponentials ΔAðλ, tÞ = A 0 ðλ, t ≥ 0Þ + f ðtÞ p X 4 n=1 A n ðλÞe −t=τnðλÞ , [1] where A n and τ n are the amplitudes and time constants for the exponential decays, respectively, A 0 is a constant term (for signal not decaying over the maximum time scale measured by the experiment, which is 2-3 ns), f is the instrument-response function (a Gaussian of width 240 fs, empirically measured using blanks), and the "*" operator represents convolution (27). We did not constrain the fitting to a specific number of decay processes, but rather let it vary as needed to obtain the best fit of the data, using up to a maximum of four exponential terms.…”

“…The samples have multiple decay pathways extending over multiple time scales, including those which have time constants much longer than can be measured with a translation stage for pump-probe delay. Therefore, we have divided the discussion into the fraction of the signal whose decay can be followed (amplitudes and time constants A 1-4 and τ [1][2][3][4] , respectively) and the longer-lived fraction (A 0 ). For the picosecond-nanosecond decays, we define the amplitude-weighted average time constant hτðλÞi = P 4 n=1 A n ðλÞτ n ðλÞ P 4 n=1 A n ðλÞ .…”

“…indium oxide | solar fuels | CO 2 hydrogenation | transient absorption | surface defects C oncerns over climate change and the projected rise in global energy demand have motivated researchers to develop alternative, more sustainable ways to generate energy from naturally abundant and renewable sources (1)(2)(3). An important challenge associated with using renewable energy sources, such as solar, is their inherent intermittent nature (4)(5)(6).…”

Hydrogen evolution in the photocatalytic reaction between methane and water in the presence of CO2 on titanate and titania supported Rh and Au catalysts

“…Recently it was shown that this type of Au cluster sufficiently catalysis certain reaction; for example it can activate the CO in CO oxidation [94,95]. We suggest that the molecular-like Au cluster may facilitate the activation of methane for transformation to dehydrogenation (13) and the coupling of methyl to ethane (16) which dominates on Au/TNT as can be seen in Table 2. It is generally accepted that the coupling of methyl radicals favored on gold [96]:…”

“…The increased emission rate of these gases, especially of CO 2 , contributes to global warming [13]. The dry reforming of CH 4 with CO 2 results in valuable syngas; this would solve the problem if atmospheric or byproduct CO 2 could be used in the reaction [14][15][16][17][18][19][20].…”