Selective Synthesis of Bismuth or Bismuth Selenide Nanosheets from a Metal Organic Precursor: Investigation of their Catalytic Performance for Water Splitting

Abstract

The development of cost-effective, functional materials that can be efficiently used for sustainable energy generation is highly desirable. Herein, a new molecular precursor of bismuth (tris(selenobenzoato)bismuth(III), [Bi(SeOCPh) 3 ]), has been used to prepare selectively Bi or Bi 2 Se 3 nanosheets via a colloidal route by the judicious control of the reaction parameters. The Bi formation mechanism was investigated, and it was observed that the trioctylphosphine (TOP) plays a crucial role in the formation of Bi. Employing the vapor deposition method resulted in the formation of exclusively Bi 2 Se 3 films at different temperatures. The synthesized nanomaterials and films were characterized by p-XRD, TEM, Raman, SEM, EDX, AFM, XPS, and UV–vis spectroscopy. A minimum sheet thickness of 3.6 nm (i.e., a thickness of 8–9 layers) was observed for bismuth, whereas a thickness of 4 nm (i.e., a thickness of 4 layers) was observed for Bi 2 Se 3 nanosheets. XPS showed surface oxidation of both materials and indicated an uncapped surface of Bi, whereas Bi 2 Se 3 had a capping layer of oleylamine, resulting in reduced surface oxidation. The potential of Bi and Bi 2 Se 3 nanosheets was tested for overall water-splitting application. The OER and HER catalytic performances of Bi 2 Se 3 indicate overpotentials of 385 mV at 10 mA cm –2 and 220 mV, with Tafel slopes of 122 and 178 mV dec –1 , respectively. In comparison, Bi showed a much lower OER activity (506 mV at 10 mA cm –2 ) but a slightly better HER (214 mV at 10 mA cm –2 ) performance. Similarly, Bi 2 Se 3 nanosheets were observed to exhibit cathodic photocurrent in photoelectrocatalytic activity, which indicated their p-type behavior.

Bismuth Selenide Nanostructured Clusters as Optical Coherence Tomography Contrast Agents: Beyond Gold-Based Particles

“…Indeed, the high-resolution Bi 4f spectrum can be fitted with two doublets (Δ = 5.3 eV) whose more intense components are centered around 158.1 and 158.9 eV, respectively. The first contribution comes from bismuth bound to selenium (in the matrix) 39 and to sulfur (in MAA), while the second likely stems from surface oxidation (BiO x ). The Se 3d spectrum was also fitted with two doublets (Δ = 0.86 eV, the intensity ratio of 0.735).…”

Iridium‐based electrocatalysts toward sustainable energy conversion

“…But for the IrP 2 (313), which is alternately terminated with P and Ir atoms, the surface provides potential sites for activating the N N bond. Hence, the HER is favorable for the (111) facet and the (313) facet is dominant for NRR (Figure 14A,B). As shown in Figure 14C, the free-energy changes revealed that the RDS is the first protonation process *N 2 + H + + e À !…”

Colloidal synthesis of metal chalcogenide nanomaterials from metal–organic precursors and capping ligand effect on electrocatalytic performance: progress, challenges and future perspectives

“…Then in situ addition of benzoyl chloride and the metal (Bi, Sb and Sn) salts produces selenobenzoate complexes. [40][41][42][43] Protocol modification allows performing the reaction at room temperature (in ethanol) instead of ammonia at −70 °C. Moreover, highly pyrophoric alkali metals were replaced by a relatively mild reagent, i.e., NaBH 4 , and the reaction time was decreased from 12 hours to one hour.…”

“…51 Similar influence of primary amines have been observed towards xanthate and chalcogeno-carboxylate precursors as well: they decompose even at room temperature by primary amines. 40,41,[52][53][54][55][56] Besides catalyzing the decomposition of precursors, the surfactant may act as a reagent as well. It was reported that the decomposition of phosphorus-containing complexes yields either a metal chalcogenide or metal phosphide in the presence of trioctylphosphine (TOP).…”

“…61,62 It is interesting to note that TOP can act as a reducing agent in the case of metalorganic precursors as well where metal has pre-formed bonds with the chalcogenide atoms. 40 The selenobenzoate complex of bismuth yielded Bi 2 Se 3 nanosheets by AACVD or by the colloidal route in oleylamine and 1-octadecene mixture. However, in the presence of TOP, the decomposition of the complex resulted in the formation of pure bismuth nanocrystals (Fig.…”