Theoretical investigation on $$\hbox {BeN}_{{2}}$$ monolayer for an efficient bifunctional water splitting catalyst

Abstract

The search for an active, stable, and abundant semiconductor-based bifunctional catalysts for solar hydrogen production will make a substantial impact on the sustainable development of the society that does not rely on fossil reserves. The photocatalytic water splitting mechanism on a $$\hbox {BeN}_{{2}}$$ BeN 2 monolayer has here been investigated by using state-of-the-art density functional theory calculations. For all possible reaction intermediates, the calculated changes in Gibbs free energy showed that the oxygen evolution reaction will occur at, and above, the potential of 2.06 V (against the NHE) as all elementary steps are exergonic. In the case of the hydrogen evolution reaction, a potential of 0.52 V, or above, was required to make the reaction take place spontaneously. Interestingly, the calculated valence band edge and conduction band edge positions for a $$\hbox {BeN}_{{2}}$$ BeN 2 monolayer are located at the potential of 2.60 V and 0.56 V, respectively. This indicates that the photo-generated holes in the valence band can oxidize water to oxygen, and the photo-generated electrons in the conduction band can spontaneously reduce water to hydrogen. Hence, the results from the present theoretical investigation show that the $$\hbox {BeN}_{{2}}$$ BeN 2 monolayer is an efficient bifunctional water-splitting catalyst, without the need for any co-catalyst.

Computational study of two-dimensional SnGe2N4 as a promising photocatalyst for the oxygen evolution reaction

“…The overall reaction under acidic conditions is given by eqn (6) 66 and the reaction steps are given by eqn (7)–(11). 67–70 2H 2 O (l) → O 2(g) + 4H + + 4e − H 2 O (l) + *→ *OH + H + + e − *OH → *O + H + + e − H 2 O (l) + *O → *O *OH + H + + e − *O *OH → *O *O + H + + e − *O *O → * + O 2(g) Overpotential was calculated using the formula,Δ G 1 , Δ G 2 and Δ G 3 in eqn (12) are the differences in reaction-free energies of the four OER steps. 62,71…”

Photocatalytic properties of anisotropic β-PtX2 (X = S, Se) and Janus β-PtSSe monolayers

“…External potentials of 5.66 V, 0.45 V, and 1.27 V were required to derive the OER process spontaneously on the surface of β-PtS 2 , β-PtSe 2 , and β-PtSSe, respectively. It can be noted that the recently reported 2D photocatalyst materials with required external potential for the OER process are β-GeSe (0.49 V), 6 C 3 N 5 (0.69 V), 10 BeN 2 (0.83 V), 7 g-CN (0.93 V), 11 Pd 3 P 2 S 8 (1.07 V), 12 GaAs (1.39 V), 8 g-C 3 N 4 (1.45 V), 91 CuCl (1.61 V), 13 Janus Pd 4 S 3 Se 3 (1.76 V), 27 and C 3 S (2.03 V). 9…”

“…The ratelimiting potential for b-PtS b-PtSe 2 , and b-PtSSe, respectively. It can be noted that the recently reported 2D photocatalyst materials with required external potential for the OER process are b-GeSe (0.49 V), 6 C 3 N 5 (0.69 V), 10 BeN 2 (0.83 V), 7 g-CN (0.93 V), 11 Pd 3 P 2 S 8 (1.07 V), 12 GaAs (1.39 V), 8 g-C 3 N 4 (1.45 V), 91 CuCl (1.61 V), 13 Janus Pd 4 S 3 Se 3 (1.76 V), 27 and C 3 S (2.03 V). 9 3.6 Solar-to-hydrogen efficiency Further, we calculated the solar-to-hydrogen efficiency, which is the product of light absorption and carrier utilization efficiency assuming 100% efficiency of the catalytic reaction: 16…”

“…To achieve highly efficient photocatalytic water splitting together with significantly reducing environmental and energy concerns, great efforts have been made to explore novel two-dimensional (2D) materials capable of harvesting sunlight with a high solar-to-hydrogen energy conversion efficiency and ability for the separation and migration of photoexcited carriers. 1,2 A variety of novel 2D materials as photocatalysts have been proposed, including PdSe 2 , 3 PdSeO 3 , 4 SiP 2 , 5 β-GeSe, 6 β-SnSe, 6 BeN 2 , 7 GaAs, 8 C 3 S, 9 C 3 N 5 , 10 g-CN, 11 Pd 3 P 2 S 8 , 12 CuCl (1.61 V), 13 AgBiP 2 Se 6 , 14 Ga 2 SSe, 15 Ga 2 S 3 , 16 HfX 3 (X = S, Se), 17 Janus MXY (M = Mo, W; XY = S, Se, Te), 18–20 Janus CrXY (XY = S, Se, Te), 21,22 Janus PdXY(XY = S, Se, Te), 23 Janus M 2 XY (M = Ga, In; XY = S, Se, Te), 24,25 Janus PdPSeX (X = O, S, Te), 26 Janus Pd 4 S 3 Se 3 , 27 and 2D honeycomb polymers. 28,29 However, due to their low energy conversion efficiency and high kinetic overpotential, only a few such 2D materials show good photocatalytic properties for water splitting.…”