Page 42 - Multifunctional Photocatalytic Materials for Energy

Metal oxide electrodes for photo-activated water splitting 31

(A)

1.8 (C)
1.6 3
(B) 1.4
J (mA¥cm –2 ) 1.2 1 2 1

0.8
0.6
0.4
0.2
0
–0.3 –0.2 –0.1 0 0.1 0.2 0.3 0.4 0.5
E (V vs. MSE)
Fig. 3.7 (A) SEM micrograph displaying silver NPs dispersed on FTO substrate on which
WO 3 films were subsequently deposited. (B) Representative TEM micrograph for Au NPs
3−
functionalized with PMo 12 O 40 ions deposited onto the surface of WO 3 films prepared by a
sol-gel route. (C) Photocurrent density/voltage curves recorded in water splitting (simulated
AM 1.5 sunlight, 1 M H 2 SO 4 solution) versus a mercury sulfate electrode (MSE) reference,
3−
promoted by: bare WO 3 photoanode (1); modified WO 3 photoanode with Au-PMo 12 O 40 NPs
deposited either on the FTO substrate (2) or on the system surface (3). WO 3 films on FTO
substrates were fabricated by a modified sol-gel approach. Gold nanoparticles modified with
·
phosphododecamolybdates were prepared by a liquid-phase route starting from HAuCl 4 xH 2 O
and H 3 PMo 12 O 40 [44].
Adapted with permission from J. Augustynski, K. Bienkowski, R. Solarska, Plasmon
resonance-enhanced photoelectrodes and photocatalysts, Coord. Chem. Rev. 325 (2016)
116–124. Copyright Elsevier B.V., 2016.

PEC water splitting tests were focused on FTO-supported WO 3 films, both as such
and with Au NPs incorporated in different configurations (Fig. 3.7C). In the first one,
3−
a WO 3 film was functionalized with PMo 12 O 40 -capped Au NPs, anchored on its sur-
face through a mild annealing (70°C, 10 min). In a second one, Au NPs were deposited
on the FTO substrate and subsequently covered by the WO 3 film. This kind of Au