Cu kα

The material’s crystal structure was measured by X-ray diffraction (XRD, CuKα (λ = 1.5406 Å BRUKER, Ettlingen, Germany). The compositions of the Ce-SPC surface were analyzed through a Fourier transform infrared spectra (FTIR, VERTEX 70,BRUKER, Ettlingen, Germany). The X-ray photoelectron spectroscopy (XPS, Axis Ultra DLD) was utilized to study the surface chemical state and molecular structure of samples.The surface morphology and microstructure of the samples were analyzed by Scanning Electron Microscope (SEM, FEI Quanta 250, Hillsboro, OR, USA). The optical properties of samples were detected by the UV-Vis spectrophotometer (Spec-3700 DUV, Shimadzu, Kyoto, Japan).The photoluminescence spectroscopy (PL) of the material was determined by a fluorescence emitter (PL, Hitachi F4500, Chiyoda, Japan). Electrochemical impedance spectroscopy (EIS) and photocurrent testing of materials are performed using a traditional three-electrode electrochemical workstation (CHI 660D). The BET specific surface area of samples was recorded on a surface area and pore size distribution analyzer (Quantachrome NOVA 2000e, Boynton Beach, FL, USA).

X-ray diffraction (Cu Kα; λ = 1.5406 Å; Bruker, Ettlingen, Germany) was employed to study the phase structure of materials. XPS using an Axis Ultra DLD system (Kratos Analytical, Manchester, UK) was applied to investigate the binding energy of elements. The surface compositions of materials were analyzed by Fourier transform infrared (FTIR) spectroscopy (Vertex 70; Bruker). SEM employing a Quanta 250 setup (FEI, Hillsboro, OR, USA) was used to study the surface morphology and microstructure. A three-electrode electrochemical workstation (CHI660D; CH Instruments, Bee Cave, TX, USA) was used to measure the photocurrent responses of materials. The surface area was measured by an analyzer (NOV 2000e; Quantachrome, Boynton Beach, FL, USA).

X-ray diffraction (XRD; Cu-Kα, 30 kV and 10 mA; Bruker D2, Germany) was used to identify the product phases of the HEOs. From the peaks in the XRD patterns, the crystallite size was calculated using Scherrer’s formula as shown in Equation (1), and the average value was taken for each sample from 1# to 6#.

D: crystallite size (nm), K: Scherrer constant (0.94) [16 ], λ = Cu Kα (0.1542 nm), β = full width at half maximum (rad), θ = Bragg’s angle (rad)

The X-ray diffraction (XRD) pattern of the HAp-CTAB composite was recorded on a Bruker D8 Advance diffractometer with nickel-filtered Cu Kα (λ = 1.5418 Å) radiation (Billerica, MA, USA). The sample was measured at room temperature. The scanning range was 20–60° in 2θ. The incremental step was 0.02° while the time per step was 0.4 s. The average crystal size of the HAp-CTAB composite powder was calculated using the Scherrer equation [22 (link)]:
where Γ is the full-width at half-maximum (FWHM), λ is the X-ray wavelength, D is the crystal size, and θ is the Bragg angle for the reflection (002).

X-ray diffraction (XRD) was used to examine the magnesium-doped hydroxyapatite (10MgHAp), 10MgHApD nanocomposites and dextran. The equipment for XRD analysis was a Bruker D8 Advance diffractometer with CuKα (λ = 1.5418 Å) radiation (Bruker, Karlsruhe, Germany), equipped with a high-efficiency LynxEye™ 1D linear detector. The patterns were achieved in the 2θ range 20–60°. The step size was 0.02° and the dwell time was 5 s.

A customised relative humidity or gas partial pressure controller was prepared (Supplementary Fig. 17). Two mass flow controllers (MFCs) with different controlling ranges (100 sccm and 5 sccm for low partial pressure of <5%) were connected to the n-C₄H₁₀ gas cylinder. Two MFCs were connected to the N₂ cylinder as a purge gas to activate the sample or control different relative humidity. The working gas was imported into the in-situ PXRD chamber (Bruker, D8 advance, Cu Kα). All the stainless-steel valves and joints were purchased from Shanghai X-tec Fluid Technology Co, Ltd, and the MFCs were purchased from Alicat Scientific (A Halma company).

Elemental analyses of (C, H, N) were performed on a PE 2400 series II CHNS/O (PerkinElmer Instruments, Shelton, CT, USA) or an Elementar Vario EL-III analyzer (Elementar Analysensysteme GmbH, Hanau, Germany). Infrared spectra were obtained from a JASCO FT/IR-460 plus spectrometer with pressed KBr pellets (JASCO, Easton, MD, USA). Powder X-ray diffraction patterns were carried out with a Bruker D8-Focus Bragg–Brentano X-ray powder diffractometer equipped with a CuKα (λ_α = 1.54178 Å) sealed tube (Bruker Corporation, Karlsruhe, Germany). The UV-Vis spectrum was performed on a UV-2450 spectrophotometer (Dongguan Hongcheng Optical Products Co., Dongguan, China). Emission spectra were determined with a Hitachi F-4500 fluorescence spectrophotometer (Hitachi, Tokyo, Japan). Energy dispersive X-ray (EDX) analysis was performed by using a JEOL JSM-7600F Ultra-High Resolution Schottky Field Emission Scanning Electron Microscope with Oxford Xmax80 energy dispersive X-ray spectrometer (JEOL, Ltd., Tokyo, Japan).