Electrically conducting palladium selenide (Pd₄Se, Pd₁₇Se₁₅, Pd₇Se₄) phases: synthesis and activity towards hydrogen evolution reaction

Abstract

Electrically conducting, continuous films of different phases of palladium selenides are synthesized by the thermolysis of single source molecular precursors. The films are found to be adherent on flat substrates such as glass, indium tin oxide and glassy carbon and are stable under electrochemical conditions. They are electrocatalytically active and in particular, for hydrogen evolution reaction. Catalytic activities with low Tafel slopes of 50-60 mV per decade are observed.

Electrochemical Dealloying of PdCu3 Nanoparticles to Achieve Pt‐like Activity for the Hydrogen Evolution Reaction

“…[2a, 3f,27] Ta fel slopei so ften used to study the rate determining step of the HER. [3b] Hence, change in Tafel slope clearly indicates the change in HER mechanism on the catalysts urface; that is, HER on the as-synthesized PdCu 3 follows the Volmer-Heyrovsky mechanism, whereas on the dealloyed catalysti tf ollows the Volmer-Tafel mechanism.T he obtained Tafel slope for the dealloyed catalyst is smaller than many highly efficient non-Pt-basedH ER electrocatalysts, such as Pd 17 Se 15 (57mVdec À1 ), [22] Pd 7 Se 4 (56 mV dec À1 ), [22] Pd 4 Se (50 mV dec À1 ), [22] PdPS (46 mV dec À1 ), [3b] Pd 2 Si (131 mV dec À1 ), [23] exfoliated MoS 2 (43 mV dec À1 ), [4] WS 2 (48 mV dec À1 ), [6] CoP (50 mV dec À1 ), [8] Cu 3 Pn anowires (50 mVdec À1 ), [9] Ni 5 P 4 -Ni 2 P nanosheets (79.1 mV dec À1 ), [7] CoPS (48 mV dec À1 ) [10] and b-Mo 2 C( 62 mV dec À1 ) [12] (Table S2). [3b] Hence, change in Tafel slope clearly indicates the change in HER mechanism on the catalysts urface; that is, HER on the as-synthesized PdCu 3 follows the Volmer-Heyrovsky mechanism, whereas on the dealloyed catalysti tf ollows the Volmer-Tafel mechanism.T he obtained Tafel slope for the dealloyed catalyst is smaller than many highly efficient non-Pt-basedH ER electrocatalysts, such as Pd 17 Se 15 (57mVdec À1 ), [22] Pd 7 Se 4 (56 mV dec À1 ), [22] Pd 4 Se (50 mV dec À1 ), [22] PdPS (46 mV dec À1 ), [3b] Pd 2 Si (131 mV dec À1 ), [23] exfoliated MoS 2 (43 mV dec À1 ), [4] WS 2 (48 mV dec À1 ), [6] CoP (50 mV dec À1 ), [8] Cu 3 Pn anowires (50 mVdec À1 ), [9] Ni 5 P 4 -Ni 2 P nanosheets (79.1 mV dec À1 ), [7] CoPS (48 mV dec À1 ) [10] and b-Mo 2 C( 62 mV dec À1 ) [12] (Table S2).…”

“…However,u nder similar conditions (withoutc onsidering similar mass loading for all the catalysts), these potential values are better than that of the other acid-stable non-Pt-based HER electrocatalysts,i ncluding PdPS [onset potential( h onset ) %À50 mV; h 10 %À90 mV], [3b] Pd 17 Se 15 (h onset %À80 mV; h 10 %À182 mV), [22] Pd 7 Se 4 (h onset % À70 mV; h 10 %À162 mV), [22] Pd 4 Se (h onset %À30 mV; h 10 % À94 mV), [22] Pd 2 Si (h 10 %À192 mV), [23] exfoliated MoS 2 (h 10 % À187 mV), [4] WS 2 (h onset %À100 mV), [6] CoS 2 /RGO-CNTc omposites (h 10 %À142 mV), [5] Ni 5 P 4 -Ni 2 Pn anosheets (h onset %À54 mV; h 10 %À120 mV), [7] CoP (h 20 %À95 mV), [8] Cu 3 Pn anowires (h onset %À62 mV; h 10 %À143 mV), [9] MoPS (h 10 %À86 mV) [11] and b-Mo 2 Cn anotubes (h onset %À82 mV; h 10 %À172 mV) [12] (Table S2). However,u nder similar conditions (withoutc onsidering similar mass loading for all the catalysts), these potential values are better than that of the other acid-stable non-Pt-based HER electrocatalysts,i ncluding PdPS [onset potential( h onset ) %À50 mV; h 10 %À90 mV], [3b] Pd 17 Se 15 (h onset %À80 mV; h 10 %À182 mV), [22] Pd 7 Se 4 (h onset % À70 mV; h 10 %À162 mV), [22] Pd 4 Se (h onset %À30 mV; h 10 % À94 mV), [22] Pd 2 Si (h 10 %À192 mV), [23] exfoliated MoS 2 (h 10 % À187 mV), [4] WS 2 (h onset %À100 mV), [6] CoS 2 /RGO-CNTc omposites (h 10 %À142 mV), [5] Ni 5 P 4 -Ni 2 Pn anosheets (h onset %À54 mV; h 10 %À120 mV), [7] CoP (h 20 %À95 mV), [8] Cu 3 Pn anowires (h onset %À62 mV; h 10 %À143 mV), [9] MoPS (h 10 %À86 mV) [11] and b-Mo 2 Cn anotubes (h onset %À82 mV; h 10 %À172 mV) [12] (Table S2).…”

“…Comparison of the present data with the literaturei sd ifficult as the mass loading are not the same. However,u nder similar conditions (withoutc onsidering similar mass loading for all the catalysts), these potential values are better than that of the other acid-stable non-Pt-based HER electrocatalysts,i ncluding PdPS [onset potential( h onset ) %À50 mV; h 10 %À90 mV], [3b] Pd 17 Se 15 (h onset %À80 mV; h 10 %À182 mV), [22] Pd 7 Se 4 (h onset % À70 mV; h 10 %À162 mV), [22] Pd 4 Se (h onset %À30 mV; h 10 % À94 mV), [22] Pd 2 Si (h 10 %À192 mV), [23] exfoliated MoS 2 (h 10 % À187 mV), [4] WS 2 (h onset %À100 mV), [6] CoS 2 /RGO-CNTc omposites (h 10 %À142 mV), [5] Ni 5 P 4 -Ni 2 Pn anosheets (h onset %À54 mV; h 10 %À120 mV), [7] CoP (h 20 %À95 mV), [8] Cu 3 Pn anowires (h onset %À62 mV; h 10 %À143 mV), [9] MoPS (h 10 %À86 mV) [11] and b-Mo 2 Cn anotubes (h onset %À82 mV; h 10 %À172 mV) [12] (Table S2). Though the effect of oleylamine on electrochemical HER and its fate during this process is not knowni nt he literature, it is well-established that presence of nitrogen on the catalyst surface in the form of doped atoms enhances the HER activity.…”

Transition Metal Selenides for Electrocatalytic Hydrogen Evolution Reaction

“…Apart from the Se powder, Kukunuri et al. synthesized a palladium selenide by using the didecyl selenide (DDSe) as Se source and heating the precursor mixture in a tubular furnace at 250 °C for 1 h, under N 2 atmosphere …”

“…The reasons for these were an intrinsic lower charge-transfer resistance of 86 Ω, a larger electrochemical surface area of 1 m 2 g À 1 and a more moderate proton binding energy value of 335.3 eV. [72] Zou et al doped the sulfur into the rhenium selenide with morphology of nanosheets vertically grown on carbon fiber paper (CFP). Among all the doping ratio, the ReSe 1.78 S 0.22 /CFP showed the best activity.…”