<?php $cat = 'Work';
$catID = get_cat_ID($cat);
$subcats = get_categories('child_of=' . $catID);
    foreach($subcats as $subcat) {
    echo '<h3>';
    echo '<a href="' . get_category_link($subcat->cat_ID) . '">';
    echo '/' . $subcat->cat_name . '';
    echo '</a></h3>';
    echo '<ul>';
    $subcat_posts = get_posts('cat=' . $subcat->cat_ID);
    foreach($subcat_posts as $subcat_post) {
        $postID = $subcat_post->ID;
    echo '<li>';
    echo '<a href="' . get_permalink($postID) . '">';
    echo get_the_title($postID);
    echo '</a></li>';
    }
    echo '</ul>';
} ?>