Ternary Co3O4/CdS/SrTiO3 core-shell pn junctions toward enhanced photocatalytic hydrogen production activity

Hollow Co3O4/CdS Nanoparticles for Photocatalytic Hydrogen Evolution and Photodegradation

“…36−38 In addition, the peak of 168.08 eV is ascribed to the edge S atoms; it can act as active sites to promote the electron diffusing. 61,62 As demonstrated, Co (∼35-fold) and CdS (∼30-fold). In 24 h cycles (Figure 4d), the ∼3.94% decreasing can be regarded as a better result and is supported by the corresponding XRD (Figure S6).…”

“…In addition, for the Co 3 O 4 /CdS nano pn junction, C dl (Co/ Cd-3) exhibits a remarkable increase to ∼1.80 × 10 −2 μF•cm −2 (Figure 8a), much larger than those of Co 3 O 4 (∼1.90 × 10 −3 μF•cm −2 ) and CdS (∼3.94 × 10 −3 μF•cm −2 ), indicating the ultrathin hollow core−shell nanostructure can increase the active sites effectively. 3,51,61,62 8d), the regulated flat-band potentials (vs RHE) are 0.685 V (Co 3 O 4 ) and −0.315 V (CdS). By correction (−0.2 V/0.2 V shift for the conduction band/valence band (CB/VB)), 3,12,30,31 the corresponding VB of Co 3 O 4 is 0.885 V and CB of CdS is −0.515 V (vs RHE), respectively.…”

“…Therefore, driven by the Co 3 O 4 /CdS pn junction, the photogenerated electron would transfer to the CdS (CB) shell for photocatalytic hydrogen evolution and photodegradation, and the photogenerated hole would transfer to the Co 3 O 4 (VB) core for matching the carrier kinetic equilibrium. 59,61,62 The photocatalytic mechanism of Co 3 O 4 /CdS is principally ascribed to the potential regulation and visible light response of the Co 3 O 4 /CdS pn junction (Figure 9) and the increased active sites of ultrathin hollow nanostructure.…”

“…59,60 Moreover, such ultrathin core−shell nanostructure can shorten the carrier transportation route to accelerate carrier diffusion, which can improve the photocatalytic performance further and inhibit the photocorrosion effectively. 61 We have proposed the ultrathin hollow core−shell nano pn junction of Co 3 O 4 /CdS with a Co-based MOFs self-template auxiliary (ZIF-67) via chemical calcination. The obtained Co 3 O 4 /CdS exhibits better photocatalytic hydrogen evolution and photodegradation than single Co 3 O 4 (∼90-fold/∼35-fold) and single CdS (∼60-fold/∼30-fold).…”

Construction of Hollow Co3O4@ZnIn2S4 p-n Heterojunctions for Highly Efficient Photocatalytic Hydrogen Production

“…Figure 7 b clearly shows the hydrogen production rate of samples with different proportions, the Co 3 O 4 (20) @ ZIS with the best proportion reaches 5.38 mmol g −1 L −1 . In addition, the hydrogen production rate first rises and then falls with the increase of the proportion of ZnIn 2 S 4 in the composite sample, which may be due to too much ZnIn 2 S 4 being loaded onto the surface of the Co 3 O 4 , thus making the active sites on Co 3 O 4 not fully exposed, and resulting in the hole not reacting with sacrificial agents in time, the increase of carrier recombination efficiency, and the decrease of hydrogen production performance [ 36 ]. Subsequently, the hydrogen production of Co 3 O 4 (20) @ ZIS is tested for a long time to test the stability of the sample.…”