Photocatalytic Reduction on Bismuth-Based p-Block Semiconductors

Abstract

With the constant increase in demand for fuel energy, research on the exploration of renewable energy source is becoming significantly critical. Herein, photocatalysis for the direct conversion of solar to chemical energy has attracted tremendous attention. In particular, due to the energy band edges mainly formed by p orbitals or s-p hybridized states, resulting in narrow band gaps and highly dispersive band structures, photocatalysts constructed from p-block elements exhibit remarkable visible-light photocatalytic activity. Taking bismuth oxyhalide-based photocatalysts, a typical family of p-block semiconductors, as an example, the following perspective mainly focuses on three significant strategies, including constituent adjustment，vacancy engineering, and the construction of heterostructures, on the design and construction of bismuth-based solar-conversion systems with high efficiencies in terms of H 2 evolution, CO 2 reduction, and N 2 fixation. Finally, our thoughts on future challenges to be overcome for the development of advanced photoreduction systems are presented.

Templated Synthesis of Nickel−Iron Layered Double Hydroxide for Enhanced Electrocatalytic Water Oxidation: Towards the Development of Non‐Precious‐Metal Catalysts

“…The NiÀFe LDH exhibits a Tafel slope of 62.7 mV, which is lower than that of the other materials, Fe-MIL-88 (127.8 mV) and Pt/C (160.4 mV) ( Figure 3C). Moreover, the Tafel slope of NiÀFe LDH not only surpass that of Fe-MIL-88 and Pt/C but also better than or comparable to previously reported various catalysts, such as Co 50 Zn 50 -C1100 (86-92 mV), [2] Cu(OH) 2 (78 mV), [11] NiÀMo MS/Cu (108 mV), [36] NiD-PCC and NiC (98 and 155 mV), [37] Ni 3 Se 2 (97.1 mV), [38] NNCNTAs (65 mV), [39] a-Ni(OH) 2 spheres (42 mV), [40] a-NiOOH/NF (76.3 mV), [41] DPUÀAu/MnO 2 -C (51 mV) [42] and more 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 details are shown in Table 1. [2,11,[36][37][38][39][40][41][42][43][44][45][46][47]…”

“…The decreased OER onset potential and increased current densities demonstrate that NiÀFe LDH is a better catalyst than the commercially available Pt/C catalyst. The onset potential observed at NiÀFe LDH (Table 1) [2,11,[36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] is much lower than the reported catalysts [2,11,36,39,40,43-45,47À52] except few materials which exhibit OER onset potentials very close to NiÀFe LDH. [37,38,41,46] To gain more insight on the activity of the materials for the OER, LSV responses of NiÀFe LDH, Fe-MIL-88 and Pt/C are recorded in 1.0 M KOH at 1 mV s À1 ( Figure 3B).…”

“…[10] These precious metal oxides suffer from scarcity, high cost and poor stability in alkaline solution so that it becomes impractical to use them on a large scale. [10] Thus, it is important to develop highly active, cost-effective and durable electrocatalysts such as first-row transition metal oxides [11] and perovskites [12] for the OER. Among these materials, layered double hydroxides (LDHs) with controllable morphology show considerable advantages for the OER.…”

Remarkable Improvement in Water Oxidation Catalysis by Moderate Heat Treatment of a Crystalline Silver‐Based Thin Film Developed In‐Situ From Silver‐ions in Acetate Solution

“…In particular, since the development of CoÀPi catalyst by Nocera and co-workers, [8] widespread attentions have been focused for the development of first-row transition metal-oxides-based electrocatalysts such as Co, Ni, Cu, Mn and Fe for the ultimate development of photoelectrochemical solar water splitting cell. [9][10][11][12][13][14][15][16][18][19][20][21][22][23][25][26][27][28][29][30][31][32][33][34][35][36] For example by the use of electrodeposition method, several efficient catalysts for OER were obtained from Co, Cu and Ni with catalytic water oxidation showing overpotential (h) in the range of 320-470 mV and encouraging performances were observed when this metal oxides were integrated with silicon photoanode. [49][50][51][52] Despite of these achievements, to date, complexes and materials based on Ru and Ir are the most efficient catalysts [40][41][42][43][44][45][46][47] known for OER among reported ones though their low abundance and high costs impede their broad applications.…”

“…Metal oxides involving Ag-O group are versatile materials and have been intensively pursued for promising application in oxidation catalysis, [48,53] sensors, [54] fuel cells, [55] all optical switching devices and optical data storage systems. [56] Since both copper and silver are in the same group of periodic table, it is expected that like copper oxides [18][19][20][21][22][23] (Cu 2 O and CuO), silver oxides (Ag 2 O and AgO) based materials also could be active as electrocatalysts for water oxidation. In line with this expectation, it is very surprising to find out that silver-based films have been rarely reported and explored as an electrocatalysts [48] for water oxidation compared to copper and other two well-explored noble metals, e. g. Ru and Ir, although silver-based materials have been shown to be photocatalyst for this process.…”