To probe the variations on the chemical structures between Ni-MOF and NiPS whisker, we conduct the FTIR spectroscopy, and the results are shown in Fig.1(b). For pristine Ni-MOF, we can observe a wide transmission peak at about 3446 cm
–1, which is the stretching vibration of O–H, verifying the existence of the intramolecular hydrogen bonds [
22,
23]. The adjacent relatively weak band at about 3180 cm
–1 corresponds to the stretching vibration of C–H of the benzene ring. A transmission peak of the asymmetric vibration of BTC is found at 1565 cm
–1, whereas the symmetric vibrations of BTC are located at 1436 and 1375 cm
–1. The sharp peak at 1624 cm
–1 indicates the presence of water in the metal coordinate sphere [
18]. Meanwhile, the strong vibration of 728 cm
–1 is attributed to the out-of-plane bending vibration of C–H in the benzene ring [
18]. In NiPS whiskers, the C–H bending band of the benzene ring has disappeared, and the peaks derived from BTC located at 1375–1624 cm
–1 are significantly suppressed (marked by an ellipse). Nevertheless, the characteristic bands of NiPS are emerged and are dominant. The above phenomena confirm the substitution reaction of organic linkers by silicate ions during the hydrothermal process. The chemical water in the phyllosilicate structures gives the stretching signals at 3628 and 3446 cm
–1, whereas the physically bonded water gives rise to the bending vibration at 1632 cm
–1 [
24]. The prominent sharp peak located at 1028 cm
–1 corresponds to the stretching vibration of Si–O–Ni [
20], and another stretching signal at 472 cm
–1 is due to the Si–O groups in NiPS [
25], as the characteristic vibrations of phyllosilicate structures. Moreover, the observed stretching vibration of Ni–OH has formed a doublet at 709 and 665 cm
–1 [
26], which is another solid proof for the successful formation of the target products.