Max Chirin

$children_category = array(
    'child_of'           => $category_id,
    'style'              => 'none',
    'orderby'            => 'slug',
    'hide_empty'         => 0,
    'exclude'    => '1',
    'use_desc_for_title' => 1,
    'hierarchical'       => 1,
    'title_li'           => '',
    'echo'               => 0,
    'separator'          => '',
    'depth'              => 0
   );
 $fuckincat =  wp_list_categories($children_category);
 $fuckincat = str_replace('<a', '<div class="col-md-4 col-sm-6 col-xs-6 block-cat"><span> <a ', $fuckincat);
 $fuckincat = str_replace('</a>', '</a></span></div>', $fuckincat);
 echo $fuckincat;