Table 1.

XPS surface chemical composition of pristine and Au-functionalized ZnO, annealed at 300 and 550 °C. The O–M percentage refers to the atomic percentage of oxygen bound to metal.

	ZnO Ann@300 °C	Au@ZnO Ann@300 °C	ZnO Ann@550 °C	Au@ZnO Ann@550 °C
C%	19.2 ± 0.5	15.4 ± 0.5	16.2 ± 0.5	12.0 ± 0.5
O(total)%	49.1 ± 0.5	43.0 ± 0.5	44.2 ± 0.5	46.0 ± 0.5
O–M%	31.5 ± 0.5	37.0 ± 0.5	39.5 ± 0.5	40.1 ± 0.5
Zn%	31.7 ± 0.5	38.5 ± 0.5	39.6 ± 0.5	40.5 ± 0.5
Au%	–	1.3 ± 0.2	–	1.5 ± 0.2
Cl%	–	1.0 ± 0.5	–	–
N%	–	0.8 ± 0.5	–	–