In situ self-exsolved ultrasmall Fe₂P quantum dots from attapulgite nanofibers as superior cocatalysts for solar hydrogen evolution

Abstract

Ultrasmall Fe2P quantum dots (Fe2P QDs) are in situ self-exsolved from attapulgite (ATP) nanofibers by a low-temperature phosphidation method and the resulting Fe2P QDs/ATP has been shown to be an active, durable, and versatile H2 evolution cocatalyst.

Upcycling endogenous Fe from coal gasification slag waste into a cocatalyst for the photocatalytic H2 evolution reaction

“…2c) and many tiny dark dots with an average size of <5 nm are observed on the surface. The distance between the adjacent lattice fringes on a single dark dot is found to be 0.206 nm, consistent with the (201) planes of hexagonal Fe 2 P. 38 Moreover, the HAADF-STEM image and the corresponding EDS elemental mapping (Fig. 2d) of Fe 2 P/CGS indicate that although the distribution of Si, Al, and O elements is still homogeneous, the distribution of Fe is concentrated on the surfaces of CGS and mainly overlaps with the distribution of the P element, further confirming the formation of Fe 2 P particles.…”

“…More importantly, in comparison with CGS, a new peak corresponding to Fe–P species occurs in the resulting Fe 2 P/CGS and the content of FeO increases as a result of partial phosphidation of Fe 2 O 3 and FeOOH. 38,43 Moreover, as evidenced by the P 2p XPS spectra in Fig. 3b, additional doublet peaks due to the formation of Fe–P species appear in the P 2p spectrum of Fe 2 P/CGS as compared to the P 2p spectrum of the CGS.…”

“…During heating, the highly reductive PH 3 gas generated from NaH 2 PO 2 decomposition will diffuse into the CGS matrix and react with the doped Fe species to exsolve Fe 2 P nanoparticles. 38,43 As shown in the scanning electron microscopy (SEM) images of Fig. 1d and e, the CGS is composed of spherical particles with a wide size distribution from 100 nm to 2 μm and the particle has a relatively smooth surface.…”

“…Technically, rather than regarding endogenous transition metals, especially Fe, in CGS as waste, 29–33 they could be considered as potential precursors for synthesizing Fe-based catalysts as many Fe compounds (FeSe 2 , 34 Fe 3 C, 35,36 and Fe 2 P 37–42 ) have been demonstrated to be excellent catalysts for various catalytic applications ranging from thermal catalysis to electrolysis and photocatalysis. On the other hand, the remaining Si and Al oxides in CGS can serve as an ideal matrix for accommodating the catalyst components.…”

Integrating biomass and minerals into photocatalysts for efficient photocatalytic N2 fixation coupled with biomass conversion

“…12 Attapulgite (ATP) is a natural iron-bearing mineral with a unique one-dimensional porous structure, excellent adsorption capacity and large number of active sites. 13 Previous studies have shown that Fe modification of ATP generates a large number of iron active sites, enabling adsorption and activation of nitrogen. 14 Furthermore, Fe-modified ATP exhibits an intrinsic crystal structure with a reduced band gap, which significantly enhances the photocatalytic performance.…”