Boron-Doped Graphene Quantum Dots (BGQDs) from Spent Coffee Ground for Glucose Sensor

Table 1

Summary of C1s core level XPS spectra of GQDs and BGQDs.

Samples	C1s functional group	Binding energy (eV)	Relative intensity (%)
GQDs	C=C	284.03	23.99
	C-C	285.20	37.62
	C-N	285.86	17.98
	C-O	286.66	12.75
	C=O	287.90	5.31
	COOH	289.03	2.33
BGQDs	C-B	283.94	13.70
	C=C	284.41	25.63
	C-C	285.18	31.90
	C-N	285.87	13.57
	C-O	286.62	7.80
	C=O	287.88	4.71
	COOH	288.97	2.67
	BC4	187.52	7.70
	BC3	189.18	25.93
	BC2O	190.21	32.48
	BCO2	191.37	33.87