C–O coupling reaction for the synthesis of di-aryl ethers catalyzed by Cu–ninhydrin@GO–Ni MNPs.

Entry	Aryl halide	Product	Time (h)	Yield (%)	TON	TOF (h−1)
1			2	98	46.2	23.11
2			2	91	42.9	21.46
3			8	95	44.8	5.60
4			11	88	41.5	3.77
5			3	94	44.3	14.77
6			9	92	43.4	4.82
7			7	93	43.9	6.27
8			12	86	40.6	3.38
9			24	90	42.4	1.77