Composites　of　titanium　(IV)　oxide　combined　with　montmorillonite　(MMT)　with　various　TiO2/MMT　were　prepared　for　photocatalysis　application.　The　prepared　samples　were　characterized　by　X-ray　diffraction　(XRD),　transmission　electron　microscopy　(TEM),　Fourier　transform　infrared　spectroscopy　(FTIR),　diffuse　reflectance　UV–visible　spectroscopy,　and　X-ray　photoelectron　spectroscopy　(XPS).　The　main　influential　factors　such　as　the　TiO2/MMT　dose,　calcined　temperature,　and　pH　value　of　the　solution　were　studied.　The　main　intermediates　of　phenol　degradation　were　determined　by　high　performance　liquid　chromatography　(HPLC).　The　results　showed　that　the　average　size　of　TiO2　nanoparticles　was　decreased　from　22.51　to　10.66 nm　through　the　immobilization　on　MMT.　The　components　in　the　interlayer　domain　were　replaced　by　titanium　pillars,　and　the　pillaring　reaction　proceeded　in　the　interlayer　domain,　the　basic　skeleton　of　MMT　was　unchanged,　and　TiO2　was　dispersed　on　the　surface　of　the　MMT.　When　the　initial　concentration　of　phenol　is　10 mg/L,　the　phenol　solution　pH　is　6,　and　the　UV　light　irradiation　time　is　240 min;　the　phenol　degradation　rate　of　30%TiO2/MMT　composite　is　89.8%,　which　is　better　than　MMT　(11.5%)　and　pure　TiO2　(58.8%).　It　shows　that　TiO2　loaded　on　MMT　improves　its　photocatalytic　activity.　The　phenol　reaction　process　detected　by　HPLC　showed　that　it　had　undergone　through　hydroquinone　and　benzoquinone,　and　finally　converted　into　maleic　acid　and　carbon　dioxide　and　small　molecules.　The　possible　photocatalysis　mechanism　is　presented.　Graphical　abstract:　[Figure　not　available:　see　fulltext.]　©　2022,　The　Author(s),　under　exclusive　licence　to　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature.